[llvm-commits] [llvm] r100233 - in /llvm/trunk: ./ include/llvm/Support/ lib/Target/ARM/ lib/Target/ARM/Disassembler/ test/MC/Disassembler/ utils/TableGen/

Johnny Chen johnny.chen at apple.com
Fri Apr 2 15:27:38 PDT 2010


Author: johnny
Date: Fri Apr  2 17:27:38 2010
New Revision: 100233

URL: http://llvm.org/viewvc/llvm-project?rev=100233&view=rev
Log:
Second try of initial ARM/Thumb disassembler check-in.  It consists of a tablgen
backend (ARMDecoderEmitter) which emits the decoder functions for ARM and Thumb,
and the disassembler core which invokes the decoder function and builds up the
MCInst based on the decoded Opcode.

Reviewed by Chris Latter and Bob Wilson.

Added:
    llvm/trunk/lib/Target/ARM/Disassembler/
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h
    llvm/trunk/lib/Target/ARM/Disassembler/Makefile
    llvm/trunk/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
    llvm/trunk/test/MC/Disassembler/arm-tests.txt
    llvm/trunk/test/MC/Disassembler/neon-tests.txt
    llvm/trunk/test/MC/Disassembler/thumb-tests.txt
    llvm/trunk/utils/TableGen/ARMDecoderEmitter.cpp
    llvm/trunk/utils/TableGen/ARMDecoderEmitter.h
Modified:
    llvm/trunk/Makefile.rules
    llvm/trunk/include/llvm/Support/MathExtras.h
    llvm/trunk/lib/Target/ARM/Makefile
    llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp
    llvm/trunk/utils/TableGen/TableGen.cpp

Modified: llvm/trunk/Makefile.rules
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/Makefile.rules?rev=100233&r1=100232&r2=100233&view=diff
==============================================================================
--- llvm/trunk/Makefile.rules (original)
+++ llvm/trunk/Makefile.rules Fri Apr  2 17:27:38 2010
@@ -1612,6 +1612,11 @@
 	$(Echo) "Building $(<F) intrinsics information with tblgen"
 	$(Verb) $(TableGen) -gen-tgt-intrinsic -o $(call SYSPATH, $@) $<
 
+$(ObjDir)/ARMGenDecoderTables.inc.tmp : ARM.td $(ObjDir)/.dir
+	$(Echo) "Building $(<F) decoder tables with tblgen"
+	$(Verb) $(TableGen) -gen-arm-decoder -o $(call SYSPATH, $@) $<
+
+
 clean-local::
 	-$(Verb) $(RM) -f $(INCFiles)
 

Modified: llvm/trunk/include/llvm/Support/MathExtras.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/MathExtras.h?rev=100233&r1=100232&r2=100233&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/MathExtras.h (original)
+++ llvm/trunk/include/llvm/Support/MathExtras.h Fri Apr  2 17:27:38 2010
@@ -457,6 +457,18 @@
   return (x < 0) ? -x : x;
 }
 
+/// SignExtend32 - Sign extend B-bit number x to 32-bit int.
+/// Usage int32_t r = SignExtend32<5>(x);
+template <unsigned B> inline int32_t SignExtend32(int32_t x) {
+  return (x << (32 - B)) >> (32 - B);
+}
+
+/// SignExtend64 - Sign extend B-bit number x to 64-bit int.
+/// Usage int64_t r = SignExtend64<5>(x);
+template <unsigned B> inline int64_t SignExtend64(int32_t x) {
+  return (x << (64 - B)) >> (64 - B);
+}
+
 } // End llvm namespace
 
 #endif

Added: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Fri Apr  2 17:27:38 2010
@@ -0,0 +1,532 @@
+//===- ARMDisassembler.cpp - Disassembler for ARM/Thumb ISA -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains code to implement the public interfaces of ARMDisassembler and
+// ThumbDisassembler, both of which are instances of MCDisassembler.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "arm-disassembler"
+
+#include "ARMDisassembler.h"
+#include "ARMDisassemblerCore.h"
+
+#include "llvm/MC/MCInst.h"
+#include "llvm/Target/TargetRegistry.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+/// ARMGenDecoderTables.inc - ARMDecoderTables.inc is tblgen'ed from
+/// ARMDecoderEmitter.cpp TableGen backend.  It contains:
+///
+/// o Mappings from opcode to ARM/Thumb instruction format
+///
+/// o static uint16_t decodeInstruction(uint32_t insn) - the decoding function
+/// for an ARM instruction.
+///
+/// o static uint16_t decodeThumbInstruction(field_t insn) - the decoding
+/// function for a Thumb instruction.
+///
+#include "../ARMGenDecoderTables.inc"
+
+namespace llvm {
+
+/// showBitVector - Use the raw_ostream to log a diagnostic message describing
+/// the inidividual bits of the instruction.
+///
+static inline void showBitVector(raw_ostream &os, const uint32_t &insn) {
+  // Split the bit position markers into more than one lines to fit 80 columns.
+  os << " 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11"
+     << " 10  9  8  7  6  5  4  3  2  1  0 \n";
+  os << "---------------------------------------------------------------"
+     << "----------------------------------\n";
+  os << '|';
+  for (unsigned i = 32; i != 0; --i) {
+    if (insn >> (i - 1) & 0x01)
+      os << " 1";
+    else
+      os << " 0";
+    os << (i%4 == 1 ? '|' : ':');
+  }
+  os << '\n';
+  // Split the bit position markers into more than one lines to fit 80 columns.
+  os << "---------------------------------------------------------------"
+     << "----------------------------------\n";
+  os << '\n';
+}
+
+/// decodeARMInstruction is a decorator function which tries special cases of
+/// instruction matching before calling the auto-generated decoder function.
+static unsigned decodeARMInstruction(uint32_t &insn) {
+  if (slice(insn, 31, 28) == 15)
+    goto AutoGenedDecoder;
+
+  // Special case processing, if any, goes here....
+
+  // LLVM combines the offset mode of A8.6.197 & A8.6.198 into STRB.
+  // The insufficient encoding information of the combined instruction confuses
+  // the decoder wrt BFC/BFI.  Therefore, we try to recover here.
+  // For BFC, Inst{27-21} = 0b0111110 & Inst{6-0} = 0b0011111.
+  // For BFI, Inst{27-21} = 0b0111110 & Inst{6-4} = 0b001 & Inst{3-0} =! 0b1111.
+  if (slice(insn, 27, 21) == 0x3e && slice(insn, 6, 4) == 1) {
+    if (slice(insn, 3, 0) == 15)
+      return ARM::BFC;
+    else
+      return ARM::BFI;
+  }
+
+  // Ditto for ADDSrs, which is a super-instruction for A8.6.7 & A8.6.8.
+  // As a result, the decoder fails to decode UMULL properly.
+  if (slice(insn, 27, 21) == 0x04 && slice(insn, 7, 4) == 9) {
+    return ARM::UMULL;
+  }
+
+  // Ditto for STR_PRE, which is a super-instruction for A8.6.194 & A8.6.195.
+  // As a result, the decoder fails to decode SBFX properly.
+  if (slice(insn, 27, 21) == 0x3d && slice(insn, 6, 4) == 5)
+    return ARM::SBFX;
+
+  // And STRB_PRE, which is a super-instruction for A8.6.197 & A8.6.198.
+  // As a result, the decoder fails to decode UBFX properly.
+  if (slice(insn, 27, 21) == 0x3f && slice(insn, 6, 4) == 5)
+    return ARM::UBFX;
+
+  // Ditto for STRT, which is a super-instruction for A8.6.210 Encoding A1 & A2.
+  // As a result, the decoder fails to deocode SSAT properly.
+  if (slice(insn, 27, 21) == 0x35 && slice(insn, 5, 4) == 1)
+    return slice(insn, 6, 6) == 0 ? ARM::SSATlsl : ARM::SSATasr;
+
+  // Ditto for RSCrs, which is a super-instruction for A8.6.146 & A8.6.147.
+  // As a result, the decoder fails to decode STRHT/LDRHT/LDRSHT/LDRSBT.
+  if (slice(insn, 27, 24) == 0) {
+    switch (slice(insn, 21, 20)) {
+    case 2:
+      switch (slice(insn, 7, 4)) {
+      case 11:
+        return ARM::STRHT;
+      default:
+        break; // fallthrough
+      }
+      break;
+    case 3:
+      switch (slice(insn, 7, 4)) {
+      case 11:
+        return ARM::LDRHT;
+      case 13:
+        return ARM::LDRSBT;
+      case 15:
+        return ARM::LDRSHT;
+      default:
+        break; // fallthrough
+      }
+      break;
+    default:
+      break;   // fallthrough
+    }
+  }
+
+  // Ditto for SBCrs, which is a super-instruction for A8.6.152 & A8.6.153.
+  // As a result, the decoder fails to decode STRH_Post/LDRD_POST/STRD_POST
+  // properly.
+  if (slice(insn, 27, 25) == 0 && slice(insn, 20, 20) == 0) {
+    unsigned PW = slice(insn, 24, 24) << 1 | slice(insn, 21, 21);
+    switch (slice(insn, 7, 4)) {
+    case 11:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::STRH;
+      case 3: // Pre-indexed
+        return ARM::STRH_PRE;
+      case 0: // Post-indexed
+        return ARM::STRH_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    case 13:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::LDRD;
+      case 3: // Pre-indexed
+        return ARM::LDRD_PRE;
+      case 0: // Post-indexed
+        return ARM::LDRD_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    case 15:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::STRD;
+      case 3: // Pre-indexed
+        return ARM::STRD_PRE;
+      case 0: // Post-indexed
+        return ARM::STRD_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    default:
+      break; // fallthrough
+    }
+  }
+
+  // Ditto for SBCSSrs, which is a super-instruction for A8.6.152 & A8.6.153.
+  // As a result, the decoder fails to decode LDRH_POST/LDRSB_POST/LDRSH_POST
+  // properly.
+  if (slice(insn, 27, 25) == 0 && slice(insn, 20, 20) == 1) {
+    unsigned PW = slice(insn, 24, 24) << 1 | slice(insn, 21, 21);
+    switch (slice(insn, 7, 4)) {
+    case 11:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::LDRH;
+      case 3: // Pre-indexed
+        return ARM::LDRH_PRE;
+      case 0: // Post-indexed
+        return ARM::LDRH_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    case 13:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::LDRSB;
+      case 3: // Pre-indexed
+        return ARM::LDRSB_PRE;
+      case 0: // Post-indexed
+        return ARM::LDRSB_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    case 15:
+      switch (PW) {
+      case 2: // Offset
+        return ARM::LDRSH;
+      case 3: // Pre-indexed
+        return ARM::LDRSH_PRE;
+      case 0: // Post-indexed
+        return ARM::LDRSH_POST;
+      default:
+        break; // fallthrough
+      }
+      break;
+    default:
+      break; // fallthrough
+    }
+  }
+
+AutoGenedDecoder:
+  // Calling the auto-generated decoder function.
+  return decodeInstruction(insn);
+}
+
+// Helper function for special case handling of LDR (literal) and friends.
+// See, for example, A6.3.7 Load word: Table A6-18 Load word.
+// See A8.6.57 T3, T4 & A8.6.60 T2 and friends for why we morphed the opcode
+// before returning it.
+static unsigned T2Morph2LoadLiteral(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return Opcode; // Return unmorphed opcode.
+
+  case ARM::t2LDRDi8:
+    return ARM::t2LDRDpci;
+
+  case ARM::t2LDR_POST:   case ARM::t2LDR_PRE:
+  case ARM::t2LDRi12:     case ARM::t2LDRi8:
+  case ARM::t2LDRs:
+    return ARM::t2LDRpci;
+
+  case ARM::t2LDRB_POST:  case ARM::t2LDRB_PRE:
+  case ARM::t2LDRBi12:    case ARM::t2LDRBi8:
+  case ARM::t2LDRBs:
+    return ARM::t2LDRBpci;
+
+  case ARM::t2LDRH_POST:  case ARM::t2LDRH_PRE:
+  case ARM::t2LDRHi12:    case ARM::t2LDRHi8:
+  case ARM::t2LDRHs:
+    return ARM::t2LDRHpci;
+
+  case ARM::t2LDRSB_POST:  case ARM::t2LDRSB_PRE:
+  case ARM::t2LDRSBi12:    case ARM::t2LDRSBi8:
+  case ARM::t2LDRSBs:
+    return ARM::t2LDRSBpci;
+
+  case ARM::t2LDRSH_POST:  case ARM::t2LDRSH_PRE:
+  case ARM::t2LDRSHi12:    case ARM::t2LDRSHi8:
+  case ARM::t2LDRSHs:
+    return ARM::t2LDRSHpci;
+  }
+}
+
+/// decodeThumbSideEffect is a decorator function which can potentially twiddle
+/// the instruction or morph the returned opcode under Thumb2.
+///
+/// First it checks whether the insn is a NEON or VFP instr; if true, bit
+/// twiddling could be performed on insn to turn it into an ARM NEON/VFP
+/// equivalent instruction and decodeInstruction is called with the transformed
+/// insn.
+///
+/// Next, there is special handling for Load byte/halfword/word instruction by
+/// checking whether Rn=0b1111 and call T2Morph2LoadLiteral() on the decoded
+/// Thumb2 instruction.  See comments below for further details.
+///
+/// Finally, one last check is made to see whether the insn is a NEON/VFP and
+/// decodeInstruction(insn) is invoked on the original insn.
+///
+/// Otherwise, decodeThumbInstruction is called with the original insn.
+static unsigned decodeThumbSideEffect(bool IsThumb2, uint32_t &insn) {
+  if (IsThumb2) {
+    uint16_t op1 = slice(insn, 28, 27);
+    uint16_t op2 = slice(insn, 26, 20);
+
+    // A6.3 32-bit Thumb instruction encoding
+    // Table A6-9 32-bit Thumb instruction encoding
+
+    // The coprocessor instructions of interest are transformed to their ARM
+    // equivalents.
+
+    // --------- Transform Begin Marker ---------
+    if ((op1 == 1 || op1 == 3) && slice(op2, 6, 4) == 7) {
+      // A7.4 Advanced SIMD data-processing instructions
+      // U bit of Thumb corresponds to Inst{24} of ARM.
+      uint16_t U = slice(op1, 1, 1);
+
+      // Inst{28-24} of ARM = {1,0,0,1,U};
+      uint16_t bits28_24 = 9 << 1 | U;
+      DEBUG(showBitVector(errs(), insn));
+      setSlice(insn, 28, 24, bits28_24);
+      return decodeInstruction(insn);
+    }
+
+    if (op1 == 3 && slice(op2, 6, 4) == 1 && slice(op2, 0, 0) == 0) {
+      // A7.7 Advanced SIMD element or structure load/store instructions
+      // Inst{27-24} of Thumb = 0b1001
+      // Inst{27-24} of ARM   = 0b0100
+      DEBUG(showBitVector(errs(), insn));
+      setSlice(insn, 27, 24, 4);
+      return decodeInstruction(insn);
+    }
+    // --------- Transform End Marker ---------
+
+    // See, for example, A6.3.7 Load word: Table A6-18 Load word.
+    // See A8.6.57 T3, T4 & A8.6.60 T2 and friends for why we morphed the opcode
+    // before returning it to our caller.
+    if (op1 == 3 && slice(op2, 6, 5) == 0 && slice(op2, 0, 0) == 1
+        && slice(insn, 19, 16) == 15)
+      return T2Morph2LoadLiteral(decodeThumbInstruction(insn));
+
+    // One last check for NEON/VFP instructions.
+    if ((op1 == 1 || op1 == 3) && slice(op2, 6, 6) == 1)
+      return decodeInstruction(insn);
+
+    // Fall through.
+  }
+
+  return decodeThumbInstruction(insn);
+}
+
+static inline bool Thumb2PreloadOpcodeNoPCI(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::t2PLDi12:   case ARM::t2PLDi8:
+  case ARM::t2PLDr:     case ARM::t2PLDs:
+  case ARM::t2PLDWi12:  case ARM::t2PLDWi8:
+  case ARM::t2PLDWr:    case ARM::t2PLDWs:
+  case ARM::t2PLIi12:   case ARM::t2PLIi8:
+  case ARM::t2PLIr:     case ARM::t2PLIs:
+    return true;
+  }
+}
+
+static inline unsigned T2Morph2Preload2PCI(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return 0;
+  case ARM::t2PLDi12:   case ARM::t2PLDi8:
+  case ARM::t2PLDr:     case ARM::t2PLDs:
+    return ARM::t2PLDpci;
+  case ARM::t2PLDWi12:  case ARM::t2PLDWi8:
+  case ARM::t2PLDWr:    case ARM::t2PLDWs:
+    return ARM::t2PLDWpci;
+  case ARM::t2PLIi12:   case ARM::t2PLIi8:
+  case ARM::t2PLIr:     case ARM::t2PLIs:
+    return ARM::t2PLIpci;
+  }
+}
+
+//
+// Public interface for the disassembler
+//
+
+bool ARMDisassembler::getInstruction(MCInst &MI,
+                                     uint64_t &Size,
+                                     const MemoryObject &Region,
+                                     uint64_t Address,
+                                     raw_ostream &os) const {
+  // The machine instruction.
+  uint32_t insn;
+
+  // We want to read exactly 4 bytes of data.
+  if (Region.readBytes(Address, 4, (uint8_t*)&insn, NULL) == -1)
+    return false;
+
+  unsigned Opcode = decodeARMInstruction(insn);
+  ARMFormat Format = ARMFormats[Opcode];
+  Size = 4;
+
+  DEBUG({
+      errs() << "Opcode=" << Opcode << " Name=" << ARMUtils::OpcodeName(Opcode)
+             << " Format=" << stringForARMFormat(Format) << '(' << (int)Format
+             << ")\n";
+      showBitVector(errs(), insn);
+    });
+
+  ARMBasicMCBuilder *Builder = CreateMCBuilder(Opcode, Format);
+
+  if (!Builder)
+    return false;
+
+  if (!Builder->Build(MI, insn))
+    return false;
+
+  delete Builder;
+
+  return true;
+}
+
+bool ThumbDisassembler::getInstruction(MCInst &MI,
+                                       uint64_t &Size,
+                                       const MemoryObject &Region,
+                                       uint64_t Address,
+                                       raw_ostream &os) const {
+  // The machine instruction.
+  uint32_t insn = 0;
+  uint32_t insn1 = 0;
+
+  // A6.1 Thumb instruction set encoding
+  //
+  // If bits [15:11] of the halfword being decoded take any of the following
+  // values, the halfword is the first halfword of a 32-bit instruction:
+  // o 0b11101
+  // o 0b11110
+  // o 0b11111.
+  //
+  // Otherwise, the halfword is a 16-bit instruction.
+
+  // Read 2 bytes of data first.
+  if (Region.readBytes(Address, 2, (uint8_t*)&insn, NULL) == -1)
+    return false;
+
+  unsigned bits15_11 = slice(insn, 15, 11);
+  bool IsThumb2 = false;
+
+  // 32-bit instructions if the bits [15:11] of the halfword matches
+  // { 0b11101 /* 0x1D */, 0b11110 /* 0x1E */, ob11111 /* 0x1F */ }.
+  if (bits15_11 == 0x1D || bits15_11 == 0x1E || bits15_11 == 0x1F) {
+    IsThumb2 = true;
+    if (Region.readBytes(Address + 2, 2, (uint8_t*)&insn1, NULL) == -1)
+      return false;
+    insn = (insn << 16 | insn1);
+  }
+
+  // The insn could potentially be bit-twiddled in order to be decoded as an ARM
+  // NEON/VFP opcode.  In such case, the modified insn is later disassembled as
+  // an ARM NEON/VFP instruction.
+  //
+  // This is a short term solution for lack of encoding bits specified for the
+  // Thumb2 NEON/VFP instructions.  The long term solution could be adding some
+  // infrastructure to have each instruction support more than one encodings.
+  // Which encoding is used would be based on which subtarget the compiler/
+  // disassembler is working with at the time.  This would allow the sharing of
+  // the NEON patterns between ARM and Thumb2, as well as potential greater
+  // sharing between the regular ARM instructions and the 32-bit wide Thumb2
+  // instructions as well.
+  unsigned Opcode = decodeThumbSideEffect(IsThumb2, insn);
+
+  // A8.6.117/119/120/121.
+  // PLD/PLDW/PLI instructions with Rn==15 is transformed to the pci variant.
+  if (Thumb2PreloadOpcodeNoPCI(Opcode) && slice(insn, 19, 16) == 15)
+    Opcode = T2Morph2Preload2PCI(Opcode);
+
+  ARMFormat Format = ARMFormats[Opcode];
+  Size = IsThumb2 ? 4 : 2;
+
+  DEBUG({
+      errs() << "Opcode=" << Opcode << " Name=" << ARMUtils::OpcodeName(Opcode)
+             << " Format=" << stringForARMFormat(Format) << '(' << (int)Format
+             << ")\n";
+      showBitVector(errs(), insn);
+    });
+
+  ARMBasicMCBuilder *Builder = CreateMCBuilder(Opcode, Format);
+  Builder->setSession(const_cast<Session *>(&SO));
+
+  if (!Builder)
+    return false;
+
+  if (!Builder->Build(MI, insn))
+    return false;
+
+  delete Builder;
+
+  return true;
+}
+
+// A8.6.50
+static unsigned short CountITSize(unsigned ITMask) {
+  // First count the trailing zeros of the IT mask.
+  unsigned TZ = CountTrailingZeros_32(ITMask);
+  assert(TZ <= 3 && "Encoding error");
+  return (4 - TZ);
+}
+
+/// Init ITState.
+void Session::InitIT(unsigned short bits7_0) {
+  ITCounter = CountITSize(slice(bits7_0, 3, 0));
+  ITState = bits7_0;
+}
+
+/// Update ITState if necessary.
+void Session::UpdateIT() {
+  assert(ITCounter);
+  --ITCounter;
+  if (ITCounter == 0)
+    ITState = 0;
+  else {
+    unsigned short NewITState4_0 = slice(ITState, 4, 0) << 1;
+    setSlice(ITState, 4, 0, NewITState4_0);
+  }
+}
+
+static MCDisassembler *createARMDisassembler(const Target &T) {
+  return new ARMDisassembler;
+}
+
+static MCDisassembler *createThumbDisassembler(const Target &T) {
+  return new ThumbDisassembler;
+}
+
+extern "C" void LLVMInitializeARMDisassembler() { 
+  // Register the disassembler.
+  TargetRegistry::RegisterMCDisassembler(TheARMTarget, 
+                                         createARMDisassembler);
+  TargetRegistry::RegisterMCDisassembler(TheThumbTarget,
+                                         createThumbDisassembler);
+}
+
+} // namespace llvm

Added: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.h Fri Apr  2 17:27:38 2010
@@ -0,0 +1,91 @@
+//===- ARMDisassembler.h - Disassembler for ARM/Thumb ISA -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains the header for ARMDisassembler and ThumbDisassembler, both are
+// subclasses of MCDisassembler.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ARMDISASSEMBLER_H
+#define ARMDISASSEMBLER_H
+
+#include "llvm/MC/MCDisassembler.h"
+
+namespace llvm {
+  
+class MCInst;
+class MemoryObject;
+class raw_ostream;
+  
+/// ARMDisassembler - ARM disassembler for all ARM platforms.
+class ARMDisassembler : public MCDisassembler {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  ARMDisassembler() :
+    MCDisassembler() {
+  }
+
+  ~ARMDisassembler() {
+  }
+
+  /// getInstruction - See MCDisassembler.
+  bool getInstruction(MCInst &instr,
+                      uint64_t &size,
+                      const MemoryObject &region,
+                      uint64_t address,
+                      raw_ostream &vStream) const;
+private:
+};
+
+// Forward declaration.
+class ARMBasicMCBuilder;
+
+/// Session - Keep track of the IT Block progression.
+class Session {
+  friend class ARMBasicMCBuilder;
+public:
+  Session() : ITCounter(0), ITState(0) {}
+  ~Session() {}
+  /// InitIT - Initializes ITCounter/ITState.
+  void InitIT(unsigned short bits7_0);
+  /// UpdateIT - Updates ITCounter/ITState as IT Block progresses.
+  void UpdateIT();
+
+private:
+  unsigned ITCounter; // Possible values: 0, 1, 2, 3, 4.
+  unsigned ITState;   // A2.5.2 Consists of IT[7:5] and IT[4:0] initially.
+};
+
+/// ThumbDisassembler - Thumb disassembler for all ARM platforms.
+class ThumbDisassembler : public MCDisassembler {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  ThumbDisassembler() :
+    MCDisassembler(), SO() {
+  }
+
+  ~ThumbDisassembler() {
+  }
+
+  /// getInstruction - See MCDisassembler.
+  bool getInstruction(MCInst &instr,
+                      uint64_t &size,
+                      const MemoryObject &region,
+                      uint64_t address,
+                      raw_ostream &vStream) const;
+private:
+  Session SO;
+};
+
+} // namespace llvm
+  
+#endif

Added: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp Fri Apr  2 17:27:38 2010
@@ -0,0 +1,3263 @@
+//===- ARMDisassemblerCore.cpp - ARM disassembler helpers -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains code to represent the core concepts of Builder, Builder Factory,
+// as well as the Algorithm to solve the problem of disassembling an ARM instr.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ARMDisassemblerCore.h"
+#include "ARMAddressingModes.h"
+
+/// ARMGenInstrInfo.inc - ARMGenInstrInfo.inc contains the static const
+/// TargetInstrDesc ARMInsts[] definition and the TargetOperandInfo[]'s
+/// describing the operand info for each ARMInsts[i].
+///
+/// Together with an instruction's encoding format, we can take advantage of the
+/// NumOperands and the OpInfo fields of the target instruction description in
+/// the quest to build out the MCOperand list for an MCInst.
+///
+/// The general guideline is that with a known format, the number of dst and src
+/// operands are well-known.  The dst is built first, followed by the src
+/// operand(s).  The operands not yet used at this point are for the Implicit
+/// Uses and Defs by this instr.  For the Uses part, the pred:$p operand is
+/// defined with two components:
+///
+/// def pred {	// Operand PredicateOperand
+///   ValueType Type = OtherVT;
+///   string PrintMethod = "printPredicateOperand";
+///   string AsmOperandLowerMethod = ?;
+///   dag MIOperandInfo = (ops i32imm, CCR);
+///   AsmOperandClass ParserMatchClass = ImmAsmOperand;
+///   dag DefaultOps = (ops (i32 14), (i32 zero_reg));
+/// }
+///
+/// which is manifested by the TargetOperandInfo[] of:
+///
+/// { 0, 0|(1<<TOI::Predicate), 0 },
+/// { ARM::CCRRegClassID, 0|(1<<TOI::Predicate), 0 }
+///
+/// So the first predicate MCOperand corresponds to the immediate part of the
+/// ARM condition field (Inst{31-28}), and the second predicate MCOperand
+/// corresponds to a register kind of ARM::CPSR.
+///
+/// For the Defs part, in the simple case of only cc_out:$s, we have:
+///
+/// def cc_out {	// Operand OptionalDefOperand
+///   ValueType Type = OtherVT;
+///   string PrintMethod = "printSBitModifierOperand";
+///   string AsmOperandLowerMethod = ?;
+///   dag MIOperandInfo = (ops CCR);
+///   AsmOperandClass ParserMatchClass = ImmAsmOperand;
+///   dag DefaultOps = (ops (i32 zero_reg));
+/// }
+///
+/// which is manifested by the one TargetOperandInfo of:
+///
+/// { ARM::CCRRegClassID, 0|(1<<TOI::OptionalDef), 0 }
+///
+/// And this maps to one MCOperand with the regsiter kind of ARM::CPSR.
+#include "ARMGenInstrInfo.inc"
+
+using namespace llvm;
+
+const char *ARMUtils::OpcodeName(unsigned Opcode) {
+  return ARMInsts[Opcode].Name;
+}
+
+// Return the register enum Based on RegClass and the raw register number.
+// For DRegPair, see comments below.
+// FIXME: Auto-gened?
+static unsigned getRegisterEnum(unsigned RegClassID, unsigned RawRegister,
+                                bool DRegPair = false) {
+
+  if (DRegPair && RegClassID == ARM::QPRRegClassID) {
+    // LLVM expects { Dd, Dd+1 } to form a super register; this is not specified
+    // in the ARM Architecture Manual as far as I understand it (A8.6.307).
+    // Therefore, we morph the RegClassID to be the sub register class and don't
+    // subsequently transform the RawRegister encoding when calculating RegNum.
+    //
+    // See also ARMinstPrinter::printOperand() wrt "dregpair" modifier part
+    // where this workaround is meant for.
+    RegClassID = ARM::DPRRegClassID;
+  }
+
+  // See also decodeNEONRd(), decodeNEONRn(), decodeNEONRm().
+  unsigned RegNum =
+    RegClassID == ARM::QPRRegClassID ? RawRegister >> 1 : RawRegister;
+
+  switch (RegNum) {
+  default:
+    break;
+  case 0:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R0;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D0;
+    case ARM::QPRRegClassID: case ARM::QPR_8RegClassID:
+    case ARM::QPR_VFP2RegClassID:
+      return ARM::Q0;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S0;
+    }
+    break;
+  case 1:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R1;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D1;
+    case ARM::QPRRegClassID: case ARM::QPR_8RegClassID:
+    case ARM::QPR_VFP2RegClassID:
+      return ARM::Q1;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S1;
+    }
+    break;
+  case 2:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R2;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D2;
+    case ARM::QPRRegClassID: case ARM::QPR_8RegClassID:
+    case ARM::QPR_VFP2RegClassID:
+      return ARM::Q2;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S2;
+    }
+    break;
+  case 3:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R3;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D3;
+    case ARM::QPRRegClassID: case ARM::QPR_8RegClassID:
+    case ARM::QPR_VFP2RegClassID:
+      return ARM::Q3;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S3;
+    }
+    break;
+  case 4:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R4;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D4;
+    case ARM::QPRRegClassID: case ARM::QPR_VFP2RegClassID: return ARM::Q4;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S4;
+    }
+    break;
+  case 5:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R5;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D5;
+    case ARM::QPRRegClassID: case ARM::QPR_VFP2RegClassID: return ARM::Q5;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S5;
+    }
+    break;
+  case 6:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R6;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D6;
+    case ARM::QPRRegClassID: case ARM::QPR_VFP2RegClassID: return ARM::Q6;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S6;
+    }
+    break;
+  case 7:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: case ARM::tGPRRegClassID: return ARM::R7;
+    case ARM::DPRRegClassID: case ARM::DPR_8RegClassID:
+    case ARM::DPR_VFP2RegClassID:
+      return ARM::D7;
+    case ARM::QPRRegClassID: case ARM::QPR_VFP2RegClassID: return ARM::Q7;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S7;
+    }
+    break;
+  case 8:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::R8;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D8;
+    case ARM::QPRRegClassID: return ARM::Q8;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S8;
+    }
+    break;
+  case 9:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::R9;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D9;
+    case ARM::QPRRegClassID: return ARM::Q9;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S9;
+    }
+    break;
+  case 10:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::R10;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D10;
+    case ARM::QPRRegClassID: return ARM::Q10;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S10;
+    }
+    break;
+  case 11:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::R11;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D11;
+    case ARM::QPRRegClassID: return ARM::Q11;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S11;
+    }
+    break;
+  case 12:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::R12;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D12;
+    case ARM::QPRRegClassID: return ARM::Q12;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S12;
+    }
+    break;
+  case 13:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::SP;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D13;
+    case ARM::QPRRegClassID: return ARM::Q13;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S13;
+    }
+    break;
+  case 14:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::LR;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D14;
+    case ARM::QPRRegClassID: return ARM::Q14;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S14;
+    }
+    break;
+  case 15:
+    switch (RegClassID) {
+    case ARM::GPRRegClassID: return ARM::PC;
+    case ARM::DPRRegClassID: case ARM::DPR_VFP2RegClassID: return ARM::D15;
+    case ARM::QPRRegClassID: return ARM::Q15;
+    case ARM::SPRRegClassID: case ARM::SPR_8RegClassID: return ARM::S15;
+    }
+    break;
+  case 16:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D16;
+    case ARM::SPRRegClassID: return ARM::S16;
+    }
+    break;
+  case 17:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D17;
+    case ARM::SPRRegClassID: return ARM::S17;
+    }
+    break;
+  case 18:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D18;
+    case ARM::SPRRegClassID: return ARM::S18;
+    }
+    break;
+  case 19:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D19;
+    case ARM::SPRRegClassID: return ARM::S19;
+    }
+    break;
+  case 20:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D20;
+    case ARM::SPRRegClassID: return ARM::S20;
+    }
+    break;
+  case 21:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D21;
+    case ARM::SPRRegClassID: return ARM::S21;
+    }
+    break;
+  case 22:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D22;
+    case ARM::SPRRegClassID: return ARM::S22;
+    }
+    break;
+  case 23:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D23;
+    case ARM::SPRRegClassID: return ARM::S23;
+    }
+    break;
+  case 24:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D24;
+    case ARM::SPRRegClassID: return ARM::S24;
+    }
+    break;
+  case 25:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D25;
+    case ARM::SPRRegClassID: return ARM::S25;
+    }
+    break;
+  case 26:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D26;
+    case ARM::SPRRegClassID: return ARM::S26;
+    }
+    break;
+  case 27:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D27;
+    case ARM::SPRRegClassID: return ARM::S27;
+    }
+    break;
+  case 28:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D28;
+    case ARM::SPRRegClassID: return ARM::S28;
+    }
+    break;
+  case 29:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D29;
+    case ARM::SPRRegClassID: return ARM::S29;
+    }
+    break;
+  case 30:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D30;
+    case ARM::SPRRegClassID: return ARM::S30;
+    }
+    break;
+  case 31:
+    switch (RegClassID) {
+    case ARM::DPRRegClassID: return ARM::D31;
+    case ARM::SPRRegClassID: return ARM::S31;
+    }
+    break;
+  }
+  assert(0 && "Invalid (RegClassID, RawRegister) combination");
+  return 0;
+}
+
+///////////////////////////////
+//                           //
+//     Utility Functions     //
+//                           //
+///////////////////////////////
+
+// Extract/Decode Rd: Inst{15-12}.
+static inline unsigned decodeRd(uint32_t insn) {
+  return (insn >> ARMII::RegRdShift) & ARMII::GPRRegMask;
+}
+
+// Extract/Decode Rn: Inst{19-16}.
+static inline unsigned decodeRn(uint32_t insn) {
+  return (insn >> ARMII::RegRnShift) & ARMII::GPRRegMask;
+}
+
+// Extract/Decode Rm: Inst{3-0}.
+static inline unsigned decodeRm(uint32_t insn) {
+  return (insn & ARMII::GPRRegMask);
+}
+
+// Extract/Decode Rs: Inst{11-8}.
+static inline unsigned decodeRs(uint32_t insn) {
+  return (insn >> ARMII::RegRsShift) & ARMII::GPRRegMask;
+}
+
+static inline unsigned getCondField(uint32_t insn) {
+  return (insn >> ARMII::CondShift);
+}
+
+static inline unsigned getIBit(uint32_t insn) {
+  return (insn >> ARMII::I_BitShift) & 1;
+}
+
+static inline unsigned getAM3IBit(uint32_t insn) {
+  return (insn >> ARMII::AM3_I_BitShift) & 1;
+}
+
+static inline unsigned getPBit(uint32_t insn) {
+  return (insn >> ARMII::P_BitShift) & 1;
+}
+
+static inline unsigned getUBit(uint32_t insn) {
+  return (insn >> ARMII::U_BitShift) & 1;
+}
+
+static inline unsigned getPUBits(uint32_t insn) {
+  return (insn >> ARMII::U_BitShift) & 3;
+}
+
+static inline unsigned getSBit(uint32_t insn) {
+  return (insn >> ARMII::S_BitShift) & 1;
+}
+
+static inline unsigned getWBit(uint32_t insn) {
+  return (insn >> ARMII::W_BitShift) & 1;
+}
+
+static inline unsigned getDBit(uint32_t insn) {
+  return (insn >> ARMII::D_BitShift) & 1;
+}
+
+static inline unsigned getNBit(uint32_t insn) {
+  return (insn >> ARMII::N_BitShift) & 1;
+}
+
+static inline unsigned getMBit(uint32_t insn) {
+  return (insn >> ARMII::M_BitShift) & 1;
+}
+
+// See A8.4 Shifts applied to a register.
+//     A8.4.2 Register controlled shifts.
+//
+// getShiftOpcForBits - getShiftOpcForBits translates from the ARM encoding bits
+// into llvm enums for shift opcode.  The API clients should pass in the value
+// encoded with two bits, so the assert stays to signal a wrong API usage.
+//
+// A8-12: DecodeRegShift()
+static inline ARM_AM::ShiftOpc getShiftOpcForBits(unsigned bits) {
+  switch (bits) {
+  default: assert(0 && "No such value"); return ARM_AM::no_shift;
+  case 0:  return ARM_AM::lsl;
+  case 1:  return ARM_AM::lsr;
+  case 2:  return ARM_AM::asr;
+  case 3:  return ARM_AM::ror;
+  }
+}
+
+// See A8.4 Shifts applied to a register.
+//     A8.4.1 Constant shifts.
+//
+// getImmShiftSE - getImmShiftSE translates from the raw ShiftOpc and raw Imm5
+// encodings into the intended ShiftOpc and shift amount.
+//
+// A8-11: DecodeImmShift()
+static inline void getImmShiftSE(ARM_AM::ShiftOpc &ShOp, unsigned &ShImm) {
+  // If type == 0b11 and imm5 == 0, we have an rrx, instead.
+  if (ShOp == ARM_AM::ror && ShImm == 0)
+    ShOp = ARM_AM::rrx;
+  // If (lsr or asr) and imm5 == 0, shift amount is 32.
+  if ((ShOp == ARM_AM::lsr || ShOp == ARM_AM::asr) && ShImm == 0)
+    ShImm = 32;
+}
+
+// getAMSubModeForBits - getAMSubModeForBits translates from the ARM encoding
+// bits Inst{24-23} (P(24) and U(23)) into llvm enums for AMSubMode.  The API
+// clients should pass in the value encoded with two bits, so the assert stays
+// to signal a wrong API usage.
+static inline ARM_AM::AMSubMode getAMSubModeForBits(unsigned bits) {
+  switch (bits) {
+  default: assert(0 && "No such value"); return ARM_AM::bad_am_submode;
+  case 1:  return ARM_AM::ia;   // P=0 U=1
+  case 3:  return ARM_AM::ib;   // P=1 U=1
+  case 0:  return ARM_AM::da;   // P=0 U=0
+  case 2:  return ARM_AM::db;   // P=1 U=0
+  }
+}
+
+////////////////////////////////////////////
+//                                        //
+//    Disassemble function definitions    //
+//                                        //
+////////////////////////////////////////////
+
+/// There is a separate Disassemble*Frm function entry for disassembly of an ARM
+/// instr into a list of MCOperands in the appropriate order, with possible dst,
+/// followed by possible src(s).
+///
+/// The processing of the predicate, and the 'S' modifier bit, if MI modifies
+/// the CPSR, is factored into ARMBasicMCBuilder's class method named
+/// TryPredicateAndSBitModifier.
+
+static bool DisassemblePseudo(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  if (Opcode == ARM::Int_MemBarrierV7 || Opcode == ARM::Int_SyncBarrierV7)
+    return true;
+
+  assert(0 && "Unexpected pseudo instruction!");
+  return false;
+}
+
+// Multiply Instructions.
+// MLA, MLS, SMLABB, SMLABT, SMLATB, SMLATT, SMLAWB, SMLAWT, SMMLA, SMMLS:
+//     Rd{19-16} Rn{3-0} Rm{11-8} Ra{15-12}
+//
+// MUL, SMMUL, SMULBB, SMULBT, SMULTB, SMULTT, SMULWB, SMULWT:
+//     Rd{19-16} Rn{3-0} Rm{11-8}
+//
+// SMLAL, SMULL, UMAAL, UMLAL, UMULL, SMLALBB, SMLALBT, SMLALTB, SMLALTT:
+//     RdLo{15-12} RdHi{19-16} Rn{3-0} Rm{11-8}
+//
+// The mapping of the multiply registers to the "regular" ARM registers, where
+// there are convenience decoder functions, is:
+//
+// Inst{15-12} => Rd
+// Inst{19-16} => Rn
+// Inst{3-0} => Rm
+// Inst{11-8} => Rs
+static bool DisassembleMulFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumDefs > 0 && "NumDefs should be greater than 0 for MulFrm");
+  assert(NumOps >= 3
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && OpInfo[2].RegClass == ARM::GPRRegClassID
+         && "Expect three register operands");
+
+  // Instructions with two destination registers have RdLo{15-12} first.
+  if (NumDefs == 2) {
+    assert(NumOps >= 4 && OpInfo[3].RegClass == ARM::GPRRegClassID &&
+           "Expect 4th register operand");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+    ++OpIdx;
+  }
+
+  // The destination register: RdHi{19-16} or Rd{19-16}.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+
+  // The two src regsiters: Rn{3-0}, then Rm{11-8}.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+  OpIdx += 3;
+
+  // Many multiply instructions (e.g., MLA) have three src registers.
+  // The third register operand is Ra{15-12}.
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// Helper routines for disassembly of coprocessor instructions.
+
+static bool LdStCopOpcode(unsigned Opcode) {
+  if ((Opcode >= ARM::LDC2L_OFFSET && Opcode <= ARM::LDC_PRE) ||
+      (Opcode >= ARM::STC2L_OFFSET && Opcode <= ARM::STC_PRE))
+    return true;
+  return false;
+}
+static bool CoprocessorOpcode(unsigned Opcode) {
+  if (LdStCopOpcode(Opcode))
+    return true;
+
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::CDP:  case ARM::CDP2:
+  case ARM::MCR:  case ARM::MCR2:  case ARM::MRC:  case ARM::MRC2:
+  case ARM::MCRR: case ARM::MCRR2: case ARM::MRRC: case ARM::MRRC2:
+    return true;
+  }
+}
+static inline unsigned GetCoprocessor(uint32_t insn) {
+  return slice(insn, 11, 8);
+}
+static inline unsigned GetCopOpc1(uint32_t insn, bool CDP) {
+  return CDP ? slice(insn, 23, 20) : slice(insn, 23, 21);
+}
+static inline unsigned GetCopOpc2(uint32_t insn) {
+  return slice(insn, 7, 5);
+}
+static inline unsigned GetCopOpc(uint32_t insn) {
+  return slice(insn, 7, 4);
+}
+// Most of the operands are in immediate forms, except Rd and Rn, which are ARM
+// core registers.
+//
+// CDP, CDP2:                cop opc1 CRd CRn CRm opc2
+//
+// MCR, MCR2, MRC, MRC2:     cop opc1 Rd CRn CRm opc2
+//
+// MCRR, MCRR2, MRRC, MRRc2: cop opc Rd Rn CRm
+//
+// LDC_OFFSET, LDC_PRE, LDC_POST: cop CRd Rn R0 [+/-]imm8:00
+// and friends
+// STC_OFFSET, STC_PRE, STC_POST: cop CRd Rn R0 [+/-]imm8:00
+// and friends
+//                                        <-- addrmode2 -->
+//
+// LDC_OPTION:                    cop CRd Rn imm8
+// and friends
+// STC_OPTION:                    cop CRd Rn imm8
+// and friends
+//
+static bool DisassembleCoprocessor(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert(NumOps >= 5 && "Num of operands >= 5 for coprocessor instr");
+
+  unsigned &OpIdx = NumOpsAdded;
+  bool OneCopOpc = (Opcode == ARM::MCRR || Opcode == ARM::MCRR2 ||
+                    Opcode == ARM::MRRC || Opcode == ARM::MRRC2);
+  // CDP/CDP2 has no GPR operand; the opc1 operand is also wider (Inst{23-20}).
+  bool NoGPR = (Opcode == ARM::CDP || Opcode == ARM::CDP2);
+  bool LdStCop = LdStCopOpcode(Opcode);
+
+  OpIdx = 0;
+
+  MI.addOperand(MCOperand::CreateImm(GetCoprocessor(insn)));
+
+  if (LdStCop) {
+    // Unindex if P:W = 0b00 --> _OPTION variant
+    unsigned PW = getPBit(insn) << 1 | getWBit(insn);
+
+    MI.addOperand(MCOperand::CreateImm(decodeRd(insn)));
+
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+
+    if (PW) {
+      MI.addOperand(MCOperand::CreateReg(0));
+      ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+      unsigned Offset = ARM_AM::getAM2Opc(AddrOpcode, slice(insn, 7, 0) << 2,
+                                          ARM_AM::no_shift);
+      MI.addOperand(MCOperand::CreateImm(Offset));
+      OpIdx = 5;
+    } else {
+      MI.addOperand(MCOperand::CreateImm(slice(insn, 7, 0)));
+      OpIdx = 4;
+    }
+  } else {
+    MI.addOperand(MCOperand::CreateImm(OneCopOpc ? GetCopOpc(insn)
+                                                 : GetCopOpc1(insn, NoGPR)));
+
+    MI.addOperand(NoGPR ? MCOperand::CreateImm(decodeRd(insn))
+                        : MCOperand::CreateReg(
+                            getRegisterEnum(ARM::GPRRegClassID,
+                                            decodeRd(insn))));
+
+    MI.addOperand(OneCopOpc ? MCOperand::CreateReg(
+                                getRegisterEnum(ARM::GPRRegClassID,
+                                                decodeRn(insn)))
+                            : MCOperand::CreateImm(decodeRn(insn)));
+
+    MI.addOperand(MCOperand::CreateImm(decodeRm(insn)));
+
+    OpIdx = 5;
+
+    if (!OneCopOpc) {
+      MI.addOperand(MCOperand::CreateImm(GetCopOpc2(insn)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+// Branch Instructions.
+// BLr9: SignExtend(Imm24:'00', 32)
+// Bcc, BLr9_pred: SignExtend(Imm24:'00', 32) Pred0 Pred1
+// SMC: ZeroExtend(imm4, 32)
+// SVC: ZeroExtend(Imm24, 32)
+//
+// Various coprocessor instructions are assigned BrFrm arbitrarily.
+// Delegates to DisassembleCoprocessor() helper function.
+//
+// MRS/MRSsys: Rd
+// MSR/MSRsys: Rm mask=Inst{19-16}
+// BXJ:        Rm
+// MSRi/MSRsysi: so_imm
+// SRSW/SRS: addrmode4:$addr mode_imm
+// RFEW/RFE: addrmode4:$addr Rn
+static bool DisassembleBrFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  if (CoprocessorOpcode(Opcode))
+    return DisassembleCoprocessor(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  // MRS and MRSsys take one GPR reg Rd.
+  if (Opcode == ARM::MRS || Opcode == ARM::MRSsys) {
+    assert(NumOps >= 1 && OpInfo[0].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+    NumOpsAdded = 1;
+    return true;
+  }
+  // BXJ takes one GPR reg Rm.
+  if (Opcode == ARM::BXJ) {
+    assert(NumOps >= 1 && OpInfo[0].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    NumOpsAdded = 1;
+    return true;
+  }
+  // MSR and MSRsys take one GPR reg Rm, followed by the mask.
+  if (Opcode == ARM::MSR || Opcode == ARM::MSRsys) {
+    assert(NumOps >= 1 && OpInfo[0].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 16)));
+    NumOpsAdded = 2;
+    return true;
+  }
+  // MSRi and MSRsysi take one so_imm operand, followed by the mask.
+  if (Opcode == ARM::MSRi || Opcode == ARM::MSRsysi) {
+    // SOImm is 4-bit rotate amount in bits 11-8 with 8-bit imm in bits 7-0.
+    // A5.2.4 Rotate amount is twice the numeric value of Inst{11-8}.
+    // See also ARMAddressingModes.h: getSOImmValImm() and getSOImmValRot().
+    unsigned Rot = (insn >> ARMII::SoRotImmShift) & 0xF;
+    unsigned Imm = insn & 0xFF;
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::rotr32(Imm, 2*Rot)));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 16)));
+    NumOpsAdded = 2;
+    return true;
+  }
+  // SRSW and SRS requires addrmode4:$addr for ${addr:submode}, followed by the
+  // mode immediate (Inst{4-0}).
+  if (Opcode == ARM::SRSW || Opcode == ARM::SRS ||
+      Opcode == ARM::RFEW || Opcode == ARM::RFE) {
+    // ARMInstPrinter::printAddrMode4Operand() prints special mode string
+    // if the base register is SP; so don't set ARM::SP.
+    MI.addOperand(MCOperand::CreateReg(0));
+    ARM_AM::AMSubMode SubMode = getAMSubModeForBits(getPUBits(insn));
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM4ModeImm(SubMode)));
+
+    if (Opcode == ARM::SRSW || Opcode == ARM::SRS)
+      MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));
+    else
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         decodeRn(insn))));
+    NumOpsAdded = 3;
+    return true;
+  }
+
+  assert((Opcode == ARM::Bcc || Opcode == ARM::BLr9 || Opcode == ARM::BLr9_pred
+          || Opcode == ARM::SMC || Opcode == ARM::SVC) &&
+         "Unexpected Opcode");
+
+  assert(NumOps >= 1 && OpInfo[0].RegClass == 0 && "Reg operand expected");
+
+  int Imm32 = 0;
+  if (Opcode == ARM::SMC) {
+    // ZeroExtend(imm4, 32) where imm24 = Inst{3-0}.
+    Imm32 = slice(insn, 3, 0);
+  } else if (Opcode == ARM::SVC) {
+    // ZeroExtend(imm24, 32) where imm24 = Inst{23-0}.
+    Imm32 = slice(insn, 23, 0);
+  } else {
+    // SignExtend(imm24:'00', 32) where imm24 = Inst{23-0}.
+    unsigned Imm26 = slice(insn, 23, 0) << 2;
+    //Imm32 = signextend<signed int, 26>(Imm26);
+    Imm32 = SignExtend32<26>(Imm26);
+
+    // When executing an ARM instruction, PC reads as the address of the current
+    // instruction plus 8.  The assembler subtracts 8 from the difference
+    // between the branch instruction and the target address, disassembler has
+    // to add 8 to compensate.
+    Imm32 += 8;
+  }
+
+  MI.addOperand(MCOperand::CreateImm(Imm32));
+  NumOpsAdded = 1;
+
+  return true;
+}
+
+// Misc. Branch Instructions.
+// BR_JTadd, BR_JTr, BR_JTm
+// BLXr9, BXr9
+// BRIND, BX_RET
+static bool DisassembleBrMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // BX_RET has only two predicate operands, do an early return.
+  if (Opcode == ARM::BX_RET)
+    return true;
+
+  // BLXr9 and BRIND take one GPR reg.
+  if (Opcode == ARM::BLXr9 || Opcode == ARM::BRIND) {
+    assert(NumOps >= 1 && OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    OpIdx = 1;
+    return true;
+  }
+
+  // BR_JTadd is an ADD with Rd = PC, (Rn, Rm) as the target and index regs.
+  if (Opcode == ARM::BR_JTadd) {
+    // InOperandList with GPR:$target and GPR:$idx regs.
+
+    assert(NumOps == 4 && "Expect 4 operands");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+
+    // Fill in the two remaining imm operands to signify build completion.
+    MI.addOperand(MCOperand::CreateImm(0));
+    MI.addOperand(MCOperand::CreateImm(0));
+
+    OpIdx = 4;
+    return true;
+  }
+
+  // BR_JTr is a MOV with Rd = PC, and Rm as the source register.
+  if (Opcode == ARM::BR_JTr) {
+    // InOperandList with GPR::$target reg.
+
+    assert(NumOps == 3 && "Expect 3 operands");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+
+    // Fill in the two remaining imm operands to signify build completion.
+    MI.addOperand(MCOperand::CreateImm(0));
+    MI.addOperand(MCOperand::CreateImm(0));
+
+    OpIdx = 3;
+    return true;
+  }
+
+  // BR_JTm is an LDR with Rt = PC.
+  if (Opcode == ARM::BR_JTm) {
+    // This is the reg/reg form, with base reg followed by +/- reg shop imm.
+    // See also ARMAddressingModes.h (Addressing Mode #2).
+
+    assert(NumOps == 5 && getIBit(insn) == 1 && "Expect 5 operands && I-bit=1");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+
+    ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+
+    // Disassemble the offset reg (Rm), shift type, and immediate shift length.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    // Inst{6-5} encodes the shift opcode.
+    ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 6, 5));
+    // Inst{11-7} encodes the imm5 shift amount.
+    unsigned ShImm = slice(insn, 11, 7);
+
+    // A8.4.1.  Possible rrx or shift amount of 32...
+    getImmShiftSE(ShOp, ShImm);
+    MI.addOperand(MCOperand::CreateImm(
+                    ARM_AM::getAM2Opc(AddrOpcode, ShImm, ShOp)));
+
+    // Fill in the two remaining imm operands to signify build completion.
+    MI.addOperand(MCOperand::CreateImm(0));
+    MI.addOperand(MCOperand::CreateImm(0));
+
+    OpIdx = 5;
+    return true;
+  }
+
+  assert(0 && "Unexpected BrMiscFrm Opcode");
+  return false;
+}
+
+static inline uint32_t getBFCInvMask(uint32_t insn) {
+  uint32_t lsb = slice(insn, 11, 7);
+  uint32_t msb = slice(insn, 20, 16);
+  uint32_t Val = 0;
+  assert(lsb <= msb && "Encoding error: lsb > msb");
+  for (uint32_t i = lsb; i <= msb; ++i)
+    Val |= (1 << i);
+  return ~Val;
+}
+
+static inline bool SaturateOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  case ARM::SSATlsl: case ARM::SSATasr: case ARM::SSAT16:
+  case ARM::USATlsl: case ARM::USATasr: case ARM::USAT16:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static inline unsigned decodeSaturatePos(unsigned Opcode, uint32_t insn) {
+  switch (Opcode) {
+  case ARM::SSATlsl:
+  case ARM::SSATasr:
+    return slice(insn, 20, 16) + 1;
+  case ARM::SSAT16:
+    return slice(insn, 19, 16) + 1;
+  case ARM::USATlsl:
+  case ARM::USATasr:
+    return slice(insn, 20, 16);
+  case ARM::USAT16:
+    return slice(insn, 19, 16);
+  default:
+    assert(0 && "Invalid opcode passed in");
+    return 0;
+  }
+}
+
+// A major complication is the fact that some of the saturating add/subtract
+// operations have Rd Rm Rn, instead of the "normal" Rd Rn Rm.
+// They are QADD, QDADD, QDSUB, and QSUB.
+static bool DisassembleDPFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  bool isUnary = isUnaryDP(TID.TSFlags);
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // Disassemble register def if there is one.
+  if (NumDefs && (OpInfo[OpIdx].RegClass == ARM::GPRRegClassID)) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+    ++OpIdx;
+  }
+
+  // Now disassemble the src operands.
+  if (OpIdx >= NumOps)
+    return false;
+
+  // SSAT/SSAT16/USAT/USAT16 has imm operand after Rd.
+  if (SaturateOpcode(Opcode)) {
+    MI.addOperand(MCOperand::CreateImm(decodeSaturatePos(Opcode, insn)));
+
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+
+    if (Opcode == ARM::SSAT16 || Opcode == ARM::USAT16) {
+      OpIdx += 2;
+      return true;
+    }
+
+    // For SSAT operand reg (Rm) has been disassembled above.
+    // Now disassemble the shift amount.
+
+    // Inst{11-7} encodes the imm5 shift amount.
+    unsigned ShAmt = slice(insn, 11, 7);
+
+    // A8.6.183.  Possible ASR shift amount of 32...
+    if (Opcode == ARM::SSATasr && ShAmt == 0)
+      ShAmt = 32;
+
+    MI.addOperand(MCOperand::CreateImm(ShAmt));
+
+    OpIdx += 3;
+    return true;
+  }
+
+  // Special-case handling of BFC/BFI/SBFX/UBFX.
+  if (Opcode == ARM::BFC || Opcode == ARM::BFI) {
+    // TIED_TO operand skipped for BFC and Inst{3-0} (Reg) for BFI.
+    MI.addOperand(MCOperand::CreateReg(Opcode == ARM::BFC ? 0
+                                       : getRegisterEnum(ARM::GPRRegClassID,
+                                                         decodeRm(insn))));
+    MI.addOperand(MCOperand::CreateImm(getBFCInvMask(insn)));
+    OpIdx += 2;
+    return true;
+  }
+  if (Opcode == ARM::SBFX || Opcode == ARM::UBFX) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 11, 7)));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 20, 16) + 1));
+    OpIdx += 3;
+    return true;
+  }
+
+  bool RmRn = (Opcode == ARM::QADD || Opcode == ARM::QDADD ||
+               Opcode == ARM::QDSUB || Opcode == ARM::QSUB);
+
+  // BinaryDP has an Rn operand.
+  if (!isUnary) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::GPRRegClassID,
+                                    RmRn ? decodeRm(insn) : decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // If this is a two-address operand, skip it, e.g., MOVCCr operand 1.
+  if (isUnary && (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1)) {
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  // Now disassemble operand 2.
+  if (OpIdx >= NumOps)
+    return false;
+
+  if (OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) {
+    // We have a reg/reg form.
+    // Assert disabled because saturating operations, e.g., A8.6.127 QASX, are
+    // routed here as well.
+    // assert(getIBit(insn) == 0 && "I_Bit != '0' reg/reg form");
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::GPRRegClassID,
+                                    RmRn? decodeRn(insn) : decodeRm(insn))));
+    ++OpIdx;
+  } else if (Opcode == ARM::MOVi16 || Opcode == ARM::MOVTi16) {
+    // We have an imm16 = imm4:imm12 (imm4=Inst{19:16}, imm12 = Inst{11:0}).
+    assert(getIBit(insn) == 1 && "I_Bit != '1' reg/imm form");
+    unsigned Imm16 = slice(insn, 19, 16) << 12 | slice(insn, 11, 0);
+    MI.addOperand(MCOperand::CreateImm(Imm16));
+    ++OpIdx;
+  } else {
+    // We have a reg/imm form.
+    // SOImm is 4-bit rotate amount in bits 11-8 with 8-bit imm in bits 7-0.
+    // A5.2.4 Rotate amount is twice the numeric value of Inst{11-8}.
+    // See also ARMAddressingModes.h: getSOImmValImm() and getSOImmValRot().
+    assert(getIBit(insn) == 1 && "I_Bit != '1' reg/imm form");
+    unsigned Rot = (insn >> ARMII::SoRotImmShift) & 0xF;
+    unsigned Imm = insn & 0xFF;
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::rotr32(Imm, 2*Rot)));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+static bool DisassembleDPSoRegFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  bool isUnary = isUnaryDP(TID.TSFlags);
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // Disassemble register def if there is one.
+  if (NumDefs && (OpInfo[OpIdx].RegClass == ARM::GPRRegClassID)) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+    ++OpIdx;
+  }
+
+  // Disassemble the src operands.
+  if (OpIdx >= NumOps)
+    return false;
+
+  // BinaryDP has an Rn operand.
+  if (!isUnary) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // If this is a two-address operand, skip it, e.g., MOVCCs operand 1.
+  if (isUnary && (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1)) {
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  // Disassemble operand 2, which consists of three components.
+  if (OpIdx + 2 >= NumOps)
+    return false;
+
+  assert((OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) &&
+         (OpInfo[OpIdx+1].RegClass == ARM::GPRRegClassID) &&
+         (OpInfo[OpIdx+2].RegClass == 0) &&
+         "Expect 3 reg operands");
+
+  // Register-controlled shifts have Inst{7} = 0 and Inst{4} = 1.
+  unsigned Rs = slice(insn, 4, 4);
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  if (Rs) {
+    // Register-controlled shifts: [Rm, Rs, shift].
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRs(insn))));
+    // Inst{6-5} encodes the shift opcode.
+    ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 6, 5));
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, 0)));
+  } else {
+    // Constant shifts: [Rm, reg0, shift_imm].
+    MI.addOperand(MCOperand::CreateReg(0)); // NoRegister
+    // Inst{6-5} encodes the shift opcode.
+    ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 6, 5));
+    // Inst{11-7} encodes the imm5 shift amount.
+    unsigned ShImm = slice(insn, 11, 7);
+
+    // A8.4.1.  Possible rrx or shift amount of 32...
+    getImmShiftSE(ShOp, ShImm);
+    MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, ShImm)));
+  }
+  OpIdx += 3;
+
+  return true;
+}
+
+static bool DisassembleLdStFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, bool isStore) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  bool isPrePost = isPrePostLdSt(TID.TSFlags);
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(((!isStore && NumDefs > 0) || (isStore && (NumDefs == 0 || isPrePost)))
+         && "Invalid arguments");
+
+  // Operand 0 of a pre- and post-indexed store is the address base writeback.
+  if (isPrePost && isStore) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // Disassemble the dst/src operand.
+  if (OpIdx >= NumOps)
+    return false;
+
+  assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+         "Reg operand expected");
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  // After dst of a pre- and post-indexed load is the address base writeback.
+  if (isPrePost && !isStore) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // Disassemble the base operand.
+  if (OpIdx >= NumOps)
+    return false;
+
+  assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+         "Reg operand expected");
+  assert((!isPrePost || (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1))
+         && "Index mode or tied_to operand expected");
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  ++OpIdx;
+
+  // For reg/reg form, base reg is followed by +/- reg shop imm.
+  // For immediate form, it is followed by +/- imm12.
+  // See also ARMAddressingModes.h (Addressing Mode #2).
+  if (OpIdx + 1 >= NumOps)
+    return false;
+
+  assert((OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) &&
+         (OpInfo[OpIdx+1].RegClass == 0) &&
+         "Expect 1 reg operand followed by 1 imm operand");
+
+  ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+  if (getIBit(insn) == 0) {
+    MI.addOperand(MCOperand::CreateReg(0));
+
+    // Disassemble the 12-bit immediate offset.
+    unsigned Imm12 = slice(insn, 11, 0);
+    unsigned Offset = ARM_AM::getAM2Opc(AddrOpcode, Imm12, ARM_AM::no_shift);
+    MI.addOperand(MCOperand::CreateImm(Offset));
+  } else {
+    // Disassemble the offset reg (Rm), shift type, and immediate shift length.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    // Inst{6-5} encodes the shift opcode.
+    ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 6, 5));
+    // Inst{11-7} encodes the imm5 shift amount.
+    unsigned ShImm = slice(insn, 11, 7);
+
+    // A8.4.1.  Possible rrx or shift amount of 32...
+    getImmShiftSE(ShOp, ShImm);
+    MI.addOperand(MCOperand::CreateImm(
+                    ARM_AM::getAM2Opc(AddrOpcode, ShImm, ShOp)));
+  }
+  OpIdx += 2;
+
+  return true;
+}
+
+static bool DisassembleLdFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+  return DisassembleLdStFrm(MI, Opcode, insn, NumOps, NumOpsAdded, false);
+}
+
+static bool DisassembleStFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+  return DisassembleLdStFrm(MI, Opcode, insn, NumOps, NumOpsAdded, true);
+}
+
+static bool HasDualReg(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::LDRD: case ARM::LDRD_PRE: case ARM::LDRD_POST:
+  case ARM::STRD: case ARM::STRD_PRE: case ARM::STRD_POST:
+    return true;
+  }  
+}
+
+static bool DisassembleLdStMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, bool isStore) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  bool isPrePost = isPrePostLdSt(TID.TSFlags);
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(((!isStore && NumDefs > 0) || (isStore && (NumDefs == 0 || isPrePost)))
+         && "Invalid arguments");
+
+  // Operand 0 of a pre- and post-indexed store is the address base writeback.
+  if (isPrePost && isStore) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  bool DualReg = HasDualReg(Opcode);
+
+  // Disassemble the dst/src operand.
+  if (OpIdx >= NumOps)
+    return false;
+
+  assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+         "Reg operand expected");
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  // Fill in LDRD and STRD's second operand.
+  if (DualReg) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn) + 1)));
+    ++OpIdx;
+  }
+
+  // After dst of a pre- and post-indexed load is the address base writeback.
+  if (isPrePost && !isStore) {
+    assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // Disassemble the base operand.
+  if (OpIdx >= NumOps)
+    return false;
+
+  assert(OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+         "Reg operand expected");
+  assert((!isPrePost || (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1))
+         && "Index mode or tied_to operand expected");
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  ++OpIdx;
+
+  // For reg/reg form, base reg is followed by +/- reg.
+  // For immediate form, it is followed by +/- imm8.
+  // See also ARMAddressingModes.h (Addressing Mode #3).
+  if (OpIdx + 1 >= NumOps)
+    return false;
+
+  assert((OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) &&
+         (OpInfo[OpIdx+1].RegClass == 0) &&
+         "Expect 1 reg operand followed by 1 imm operand");
+
+  ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+  if (getAM3IBit(insn) == 1) {
+    MI.addOperand(MCOperand::CreateReg(0));
+
+    // Disassemble the 8-bit immediate offset.
+    unsigned Imm4H = (insn >> ARMII::ImmHiShift) & 0xF;
+    unsigned Imm4L = insn & 0xF;
+    unsigned Offset = ARM_AM::getAM3Opc(AddrOpcode, (Imm4H << 4) | Imm4L);
+    MI.addOperand(MCOperand::CreateImm(Offset));
+  } else {
+    // Disassemble the offset reg (Rm).
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    unsigned Offset = ARM_AM::getAM3Opc(AddrOpcode, 0);
+    MI.addOperand(MCOperand::CreateImm(Offset));
+  }
+  OpIdx += 2;
+
+  return true;
+}
+
+static bool DisassembleLdMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+  return DisassembleLdStMiscFrm(MI, Opcode, insn, NumOps, NumOpsAdded, false);
+}
+
+static bool DisassembleStMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+  return DisassembleLdStMiscFrm(MI, Opcode, insn, NumOps, NumOpsAdded, true);
+}
+
+// The algorithm for disassembly of LdStMulFrm is different from others because
+// it explicitly populates the two predicate operands after operand 0 (the base)
+// and operand 1 (the AM4 mode imm).  After operand 3, we need to populate the
+// reglist with each affected register encoded as an MCOperand.
+static bool DisassembleLdStMulFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 5 && "LdStMulFrm expects NumOps >= 5");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned Base = getRegisterEnum(ARM::GPRRegClassID, decodeRn(insn));
+
+  // Writeback to base, if necessary.
+  if (Opcode == ARM::LDM_UPD || Opcode == ARM::STM_UPD) {
+    MI.addOperand(MCOperand::CreateReg(Base));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(Base));
+
+  ARM_AM::AMSubMode SubMode = getAMSubModeForBits(getPUBits(insn));
+  MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM4ModeImm(SubMode)));
+
+  // Handling the two predicate operands before the reglist.
+  int64_t CondVal = insn >> ARMII::CondShift;
+  MI.addOperand(MCOperand::CreateImm(CondVal == 0xF ? 0xE : CondVal));
+  MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+
+  OpIdx += 4;
+
+  // Fill the variadic part of reglist.
+  unsigned RegListBits = insn & ((1 << 16) - 1);
+  for (unsigned i = 0; i < 16; ++i) {
+    if ((RegListBits >> i) & 1) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         i)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+// LDREX, LDREXB, LDREXH: Rd Rn
+// LDREXD:                Rd Rd+1 Rn
+// STREX, STREXB, STREXH: Rd Rm Rn
+// STREXD:                Rd Rm Rm+1 Rn
+//
+// SWP, SWPB:             Rd Rm Rn
+static bool DisassembleLdStExFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && "Expect 2 reg operands");
+
+  bool isStore = slice(insn, 20, 20) == 0;
+  bool isDW = (Opcode == ARM::LDREXD || Opcode == ARM::STREXD);
+
+  // Add the destination operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  // Store register Exclusive needs a source operand.
+  if (isStore) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    ++OpIdx;
+
+    if (isDW) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         decodeRm(insn)+1)));
+      ++OpIdx;
+    }
+  } else if (isDW) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn)+1)));
+    ++OpIdx;
+  }
+
+  // Finally add the pointer operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  ++OpIdx;
+
+  return true;
+}
+
+// Misc. Arithmetic Instructions.
+// CLZ: Rd Rm
+// PKHBT, PKHTB: Rd Rn Rm , LSL/ASR #imm5
+// RBIT, REV, REV16, REVSH: Rd Rm
+static bool DisassembleArithMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && "Expect 2 reg operands");
+
+  bool ThreeReg = NumOps > 2 && OpInfo[2].RegClass == ARM::GPRRegClassID;
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  if (ThreeReg) {
+    assert(NumOps >= 4 && "Expect >= 4 operands");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  ++OpIdx;
+
+  // If there is still an operand info left which is an immediate operand, add
+  // an additional imm5 LSL/ASR operand.
+  if (ThreeReg && OpInfo[OpIdx].RegClass == 0
+      && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // Extract the 5-bit immediate field Inst{11-7}.
+    unsigned ShiftAmt = (insn >> ARMII::ShiftShift) & 0x1F;
+    MI.addOperand(MCOperand::CreateImm(ShiftAmt));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// Extend instructions.
+// SXT* and UXT*: Rd [Rn] Rm [rot_imm].
+// The 2nd operand register is Rn and the 3rd operand regsiter is Rm for the
+// three register operand form.  Otherwise, Rn=0b1111 and only Rm is used.
+static bool DisassembleExtFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && "Expect 2 reg operands");
+
+  bool ThreeReg = NumOps > 2 && OpInfo[2].RegClass == ARM::GPRRegClassID;
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  if (ThreeReg) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  ++OpIdx;
+
+  // If there is still an operand info left which is an immediate operand, add
+  // an additional rotate immediate operand.
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+      && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // Extract the 2-bit rotate field Inst{11-10}.
+    unsigned rot = (insn >> ARMII::ExtRotImmShift) & 3;
+    // Rotation by 8, 16, or 24 bits.
+    MI.addOperand(MCOperand::CreateImm(rot << 3));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+/////////////////////////////////////
+//                                 //
+//    Utility Functions For VFP    //
+//                                 //
+/////////////////////////////////////
+
+// Extract/Decode Dd/Sd:
+//
+// SP => d = UInt(Vd:D)
+// DP => d = UInt(D:Vd)
+static unsigned decodeVFPRd(uint32_t insn, bool isSPVFP) {
+  return isSPVFP ? (decodeRd(insn) << 1 | getDBit(insn))
+                 : (decodeRd(insn) | getDBit(insn) << 4);
+}
+
+// Extract/Decode Dn/Sn:
+//
+// SP => n = UInt(Vn:N)
+// DP => n = UInt(N:Vn)
+static unsigned decodeVFPRn(uint32_t insn, bool isSPVFP) {
+  return isSPVFP ? (decodeRn(insn) << 1 | getNBit(insn))
+                 : (decodeRn(insn) | getNBit(insn) << 4);
+}
+
+// Extract/Decode Dm/Sm:
+//
+// SP => m = UInt(Vm:M)
+// DP => m = UInt(M:Vm)
+static unsigned decodeVFPRm(uint32_t insn, bool isSPVFP) {
+  return isSPVFP ? (decodeRm(insn) << 1 | getMBit(insn))
+                 : (decodeRm(insn) | getMBit(insn) << 4);
+}
+
+// A7.5.1
+#if 0
+static uint64_t VFPExpandImm(unsigned char byte, unsigned N) {
+  assert(N == 32 || N == 64);
+
+  uint64_t Result;
+  unsigned bit6 = slice(byte, 6, 6);
+  if (N == 32) {
+    Result = slice(byte, 7, 7) << 31 | slice(byte, 5, 0) << 19;
+    if (bit6)
+      Result |= 0x1f << 25;
+    else
+      Result |= 0x1 << 30;
+  } else {
+    Result = (uint64_t)slice(byte, 7, 7) << 63 |
+             (uint64_t)slice(byte, 5, 0) << 48;
+    if (bit6)
+      Result |= 0xffL << 54;
+    else
+      Result |= 0x1L << 62;
+  }
+  return Result;
+}
+#endif
+
+// VFP Unary Format Instructions:
+//
+// VCMP[E]ZD, VCMP[E]ZS: compares one floating-point register with zero
+// VCVTDS, VCVTSD: converts between double-precision and single-precision
+// The rest of the instructions have homogeneous [VFP]Rd and [VFP]Rm registers.
+static bool DisassembleVFPUnaryFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 1 && "VFPUnaryFrm expects NumOps >= 1");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned RegClass = OpInfo[OpIdx].RegClass;
+  assert((RegClass == ARM::SPRRegClassID || RegClass == ARM::DPRRegClassID) &&
+         "Reg operand expected");
+  bool isSP = (RegClass == ARM::SPRRegClassID);
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass, decodeVFPRd(insn, isSP))));
+  ++OpIdx;
+
+  // Early return for compare with zero instructions.
+  if (Opcode == ARM::VCMPEZD || Opcode == ARM::VCMPEZS
+      || Opcode == ARM::VCMPZD || Opcode == ARM::VCMPZS)
+    return true;
+
+  RegClass = OpInfo[OpIdx].RegClass;
+  assert((RegClass == ARM::SPRRegClassID || RegClass == ARM::DPRRegClassID) &&
+         "Reg operand expected");
+  isSP = (RegClass == ARM::SPRRegClassID);
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass, decodeVFPRm(insn, isSP))));
+  ++OpIdx;
+
+  return true;
+}
+
+// All the instructions have homogeneous [VFP]Rd, [VFP]Rn, and [VFP]Rm regs.
+// Some of them have operand constraints which tie the first operand in the
+// InOperandList to that of the dst.  As far as asm printing is concerned, this
+// tied_to operand is simply skipped.
+static bool DisassembleVFPBinaryFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 3 && "VFPBinaryFrm expects NumOps >= 3");
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned RegClass = OpInfo[OpIdx].RegClass;
+  assert((RegClass == ARM::SPRRegClassID || RegClass == ARM::DPRRegClassID) &&
+         "Reg operand expected");
+  bool isSP = (RegClass == ARM::SPRRegClassID);
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass, decodeVFPRd(insn, isSP))));
+  ++OpIdx;
+
+  // Skip tied_to operand constraint.
+  if (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1) {
+    assert(NumOps >= 4 && "Expect >=4 operands");
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass, decodeVFPRn(insn, isSP))));
+  ++OpIdx;
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass, decodeVFPRm(insn, isSP))));
+  ++OpIdx;
+
+  return true;
+}
+
+// A8.6.295 vcvt (floating-point <-> integer)
+// Int to FP: VSITOD, VSITOS, VUITOD, VUITOS
+// FP to Int: VTOSI[Z|R]D, VTOSI[Z|R]S, VTOUI[Z|R]D, VTOUI[Z|R]S
+// 
+// A8.6.297 vcvt (floating-point and fixed-point)
+// Dd|Sd Dd|Sd(TIED_TO) #fbits(= 16|32 - UInt(imm4:i))
+static bool DisassembleVFPConv1Frm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 2 && "VFPConv1Frm expects NumOps >= 2");
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  bool SP = slice(insn, 8, 8) == 0; // A8.6.295 & A8.6.297
+  bool fixed_point = slice(insn, 17, 17) == 1; // A8.6.297
+  unsigned RegClassID = SP ? ARM::SPRRegClassID : ARM::DPRRegClassID;
+
+  if (fixed_point) {
+    // A8.6.297
+    assert(NumOps >= 3 && "Expect >= 3 operands");
+    int size = slice(insn, 7, 7) == 0 ? 16 : 32;
+    int fbits = size - (slice(insn,3,0) << 1 | slice(insn,5,5));
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(RegClassID,
+                                    decodeVFPRd(insn, SP))));
+
+    assert(TID.getOperandConstraint(1, TOI::TIED_TO) != -1 &&
+           "Tied to operand expected");
+    MI.addOperand(MI.getOperand(0));
+
+    assert(OpInfo[2].RegClass == 0 && !OpInfo[2].isPredicate() &&
+           !OpInfo[2].isOptionalDef() && "Imm operand expected");
+    MI.addOperand(MCOperand::CreateImm(fbits));
+
+    NumOpsAdded = 3;
+  } else {
+    // A8.6.295
+    // The Rd (destination) and Rm (source) bits have different interpretations
+    // depending on their single-precisonness.
+    unsigned d, m;
+    if (slice(insn, 18, 18) == 1) { // to_integer operation
+      d = decodeVFPRd(insn, true /* Is Single Precision */);
+      MI.addOperand(MCOperand::CreateReg(
+                      getRegisterEnum(ARM::SPRRegClassID, d)));
+      m = decodeVFPRm(insn, SP);
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClassID, m)));
+    } else {
+      d = decodeVFPRd(insn, SP);
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClassID, d)));
+      m = decodeVFPRm(insn, true /* Is Single Precision */);
+      MI.addOperand(MCOperand::CreateReg(
+                      getRegisterEnum(ARM::SPRRegClassID, m)));
+    }
+    NumOpsAdded = 2;
+  }
+
+  return true;
+}
+
+// VMOVRS - A8.6.330
+// Rt => Rd; Sn => UInt(Vn:N)
+static bool DisassembleVFPConv2Frm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 2 && "VFPConv2Frm expects NumOps >= 2");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                     decodeVFPRn(insn, true))));
+  NumOpsAdded = 2;
+  return true;
+}
+
+// VMOVRRD - A8.6.332
+// Rt => Rd; Rt2 => Rn; Dm => UInt(M:Vm)
+//
+// VMOVRRS - A8.6.331
+// Rt => Rd; Rt2 => Rn; Sm => UInt(Vm:M); Sm1 = Sm+1
+static bool DisassembleVFPConv3Frm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 3 && "VFPConv3Frm expects NumOps >= 3");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  OpIdx = 2;
+
+  if (OpInfo[OpIdx].RegClass == ARM::SPRRegClassID) {
+    unsigned Sm = decodeVFPRm(insn, true);
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                       Sm)));
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                       Sm+1)));
+    OpIdx += 2;
+  } else {
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::DPRRegClassID,
+                                    decodeVFPRm(insn, false))));
+    ++OpIdx;
+  }
+  return true;
+}
+
+// VMOVSR - A8.6.330
+// Rt => Rd; Sn => UInt(Vn:N)
+static bool DisassembleVFPConv4Frm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 2 && "VFPConv4Frm expects NumOps >= 2");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                     decodeVFPRn(insn, true))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  NumOpsAdded = 2;
+  return true;
+}
+
+// VMOVDRR - A8.6.332
+// Rt => Rd; Rt2 => Rn; Dm => UInt(M:Vm)
+//
+// VMOVRRS - A8.6.331
+// Rt => Rd; Rt2 => Rn; Sm => UInt(Vm:M); Sm1 = Sm+1
+static bool DisassembleVFPConv5Frm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 3 && "VFPConv5Frm expects NumOps >= 3");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  if (OpInfo[OpIdx].RegClass == ARM::SPRRegClassID) {
+    unsigned Sm = decodeVFPRm(insn, true);
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                       Sm)));
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::SPRRegClassID,
+                                                       Sm+1)));
+    OpIdx += 2;
+  } else {
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::DPRRegClassID,
+                                    decodeVFPRm(insn, false))));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  OpIdx += 2;
+  return true;
+}
+
+// VFP Load/Store Instructions.
+// VLDRD, VLDRS, VSTRD, VSTRS
+static bool DisassembleVFPLdStFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 3 && "VFPLdStFrm expects NumOps >= 3");
+
+  bool isSPVFP = (Opcode == ARM::VLDRS || Opcode == ARM::VSTRS) ? true : false;
+  unsigned RegClassID = isSPVFP ? ARM::SPRRegClassID : ARM::DPRRegClassID;
+
+  // Extract Dd/Sd for operand 0.
+  unsigned RegD = decodeVFPRd(insn, isSPVFP);
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClassID, RegD)));
+
+  unsigned Base = getRegisterEnum(ARM::GPRRegClassID, decodeRn(insn));
+  MI.addOperand(MCOperand::CreateReg(Base));
+
+  // Next comes the AM5 Opcode.
+  ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+  unsigned char Imm8 = insn & 0xFF;
+  MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(AddrOpcode, Imm8)));
+
+  NumOpsAdded = 3;
+
+  return true;
+}
+
+// VFP Load/Store Multiple Instructions.
+// This is similar to the algorithm for LDM/STM in that operand 0 (the base) and
+// operand 1 (the AM5 mode imm) is followed by two predicate operands.  It is
+// followed by a reglist of either DPR(s) or SPR(s).
+//
+// VLDMD[_UPD], VLDMS[_UPD], VSTMD[_UPD], VSTMS[_UPD]
+static bool DisassembleVFPLdStMulFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(NumOps >= 5 && "VFPLdStMulFrm expects NumOps >= 5");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned Base = getRegisterEnum(ARM::GPRRegClassID, decodeRn(insn));
+
+  // Writeback to base, if necessary.
+  if (Opcode == ARM::VLDMD_UPD || Opcode == ARM::VLDMS_UPD ||
+      Opcode == ARM::VSTMD_UPD || Opcode == ARM::VSTMS_UPD) {
+    MI.addOperand(MCOperand::CreateReg(Base));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(Base));
+
+  // Next comes the AM5 Opcode.
+  ARM_AM::AMSubMode SubMode = getAMSubModeForBits(getPUBits(insn));
+  unsigned char Imm8 = insn & 0xFF;
+  MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM5Opc(SubMode, Imm8)));
+
+  // Handling the two predicate operands before the reglist.
+  int64_t CondVal = insn >> ARMII::CondShift;
+  MI.addOperand(MCOperand::CreateImm(CondVal == 0xF ? 0xE : CondVal));
+  MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+
+  OpIdx += 4;
+
+  bool isSPVFP = (Opcode == ARM::VLDMS || Opcode == ARM::VLDMS_UPD ||
+     Opcode == ARM::VSTMS || Opcode == ARM::VSTMS_UPD) ? true : false;
+  unsigned RegClassID = isSPVFP ? ARM::SPRRegClassID : ARM::DPRRegClassID;
+
+  // Extract Dd/Sd.
+  unsigned RegD = decodeVFPRd(insn, isSPVFP);
+
+  // Fill the variadic part of reglist.
+  unsigned Regs = isSPVFP ? Imm8 : Imm8/2;
+  for (unsigned i = 0; i < Regs; ++i) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClassID,
+                                                       RegD + i)));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// Misc. VFP Instructions.
+// FMSTAT (vmrs with Rt=0b1111, i.e., to apsr_nzcv and no register operand)
+// FCONSTD (DPR and a VFPf64Imm operand)
+// FCONSTS (SPR and a VFPf32Imm operand)
+// VMRS/VMSR (GPR operand)
+static bool DisassembleVFPMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  if (Opcode == ARM::FMSTAT)
+    return true;
+
+  assert(NumOps >= 2 && "VFPMiscFrm expects >=2 operands");
+
+  unsigned RegEnum = 0;
+  switch (OpInfo[0].RegClass) {
+  case ARM::DPRRegClassID:
+    RegEnum = getRegisterEnum(ARM::DPRRegClassID, decodeVFPRd(insn, false));
+    break;
+  case ARM::SPRRegClassID:
+    RegEnum = getRegisterEnum(ARM::SPRRegClassID, decodeVFPRd(insn, true));
+    break;
+  case ARM::GPRRegClassID:
+    RegEnum = getRegisterEnum(ARM::GPRRegClassID, decodeRd(insn));
+    break;
+  default:
+    assert(0 && "Invalid reg class id");
+    return false;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(RegEnum));
+  ++OpIdx;
+
+  // Extract/decode the f64/f32 immediate.
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+        && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // The asm syntax specifies the before-expanded <imm>.
+    // Not VFPExpandImm(slice(insn,19,16) << 4 | slice(insn, 3, 0),
+    //                  Opcode == ARM::FCONSTD ? 64 : 32)
+    MI.addOperand(MCOperand::CreateImm(slice(insn,19,16)<<4 | slice(insn,3,0)));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// DisassembleThumbFrm() is defined in ThumbDisassemblerCore.h file.
+#include "ThumbDisassemblerCore.h"
+
+/////////////////////////////////////////////////////
+//                                                 //
+//     Utility Functions For ARM Advanced SIMD     //
+//                                                 //
+/////////////////////////////////////////////////////
+
+// The following NEON namings are based on A8.6.266 VABA, VABAL.  Notice that
+// A8.6.303 VDUP (ARM core register)'s D/Vd pair is the N/Vn pair of VABA/VABAL.
+
+// A7.3 Register encoding
+
+// Extract/Decode NEON D/Vd:
+//
+// Note that for quadword, Qd = UInt(D:Vd<3:1>) = Inst{22:15-13}, whereas for
+// doubleword, Dd = UInt(D:Vd).  We compensate for this difference by
+// handling it in the getRegisterEnum() utility function.
+// D = Inst{22}, Vd = Inst{15-12}
+static unsigned decodeNEONRd(uint32_t insn) {
+  return ((insn >> ARMII::NEON_D_BitShift) & 1) << 4
+    | (insn >> ARMII::NEON_RegRdShift) & ARMII::NEONRegMask;
+}
+
+// Extract/Decode NEON N/Vn:
+//
+// Note that for quadword, Qn = UInt(N:Vn<3:1>) = Inst{7:19-17}, whereas for
+// doubleword, Dn = UInt(N:Vn).  We compensate for this difference by
+// handling it in the getRegisterEnum() utility function.
+// N = Inst{7}, Vn = Inst{19-16}
+static unsigned decodeNEONRn(uint32_t insn) {
+  return ((insn >> ARMII::NEON_N_BitShift) & 1) << 4
+    | (insn >> ARMII::NEON_RegRnShift) & ARMII::NEONRegMask;
+}
+
+// Extract/Decode NEON M/Vm:
+//
+// Note that for quadword, Qm = UInt(M:Vm<3:1>) = Inst{5:3-1}, whereas for
+// doubleword, Dm = UInt(M:Vm).  We compensate for this difference by
+// handling it in the getRegisterEnum() utility function.
+// M = Inst{5}, Vm = Inst{3-0}
+static unsigned decodeNEONRm(uint32_t insn) {
+  return ((insn >> ARMII::NEON_M_BitShift) & 1) << 4
+    | (insn >> ARMII::NEON_RegRmShift) & ARMII::NEONRegMask;
+}
+
+namespace {
+enum ElemSize {
+  ESizeNA = 0,
+  ESize8 = 8,
+  ESize16 = 16,
+  ESize32 = 32,
+  ESize64 = 64
+};
+} // End of unnamed namespace
+
+// size        field -> Inst{11-10}
+// index_align field -> Inst{7-4}
+//
+// The Lane Index interpretation depends on the Data Size:
+//   8  (encoded as size = 0b00) -> Index = index_align[3:1]
+//   16 (encoded as size = 0b01) -> Index = index_align[3:2]
+//   32 (encoded as size = 0b10) -> Index = index_align[3]
+//
+// Ref: A8.6.317 VLD4 (single 4-element structure to one lane).
+static unsigned decodeLaneIndex(uint32_t insn) {
+  unsigned size = insn >> 10 & 3;
+  assert((size == 0 || size == 1 || size == 2) &&
+         "Encoding error: size should be either 0, 1, or 2");
+
+  unsigned index_align = insn >> 4 & 0xF;
+  return (index_align >> 1) >> size;
+}
+
+// imm64 = AdvSIMDExpandImm(op, cmode, i:imm3:imm4)
+// op = Inst{5}, cmode = Inst{11-8}
+// i = Inst{24} (ARM architecture)
+// imm3 = Inst{18-16}, imm4 = Inst{3-0}
+// Ref: Table A7-15 Modified immediate values for Advanced SIMD instructions.
+static uint64_t decodeN1VImm(uint32_t insn, ElemSize esize) {
+  unsigned char cmode = (insn >> 8) & 0xF;
+  unsigned char Imm8 = ((insn >> 24) & 1) << 7 |
+                       ((insn >> 16) & 7) << 4 |
+                       (insn & 0xF);
+  uint64_t Imm64 = 0;
+
+  switch (esize) {
+  case ESize8:
+    Imm64 = Imm8;
+    break;
+  case ESize16:
+    Imm64 = Imm8 << 8*(cmode >> 1 & 1);
+    break;
+  case ESize32: {
+    if (cmode == 12)
+      Imm64 = (Imm8 << 8) | 0xFF;
+    else if (cmode == 13)
+      Imm64 = (Imm8 << 16) | 0xFFFF;
+    else {
+      // Imm8 to be shifted left by how many bytes...
+      Imm64 = Imm8 << 8*(cmode >> 1 & 3);
+    }
+    break;
+  }
+  case ESize64: {
+    for (unsigned i = 0; i < 8; ++i)
+      if ((Imm8 >> i) & 1)
+        Imm64 |= 0xFF << 8*i;
+    break;
+  }
+  default:
+    assert(0 && "Unreachable code!");
+    return 0;
+  }
+
+  return Imm64;
+}
+
+// A8.6.339 VMUL, VMULL (by scalar)
+// ESize16 => m = Inst{2-0} (Vm<2:0>) D0-D7
+// ESize32 => m = Inst{3-0} (Vm<3:0>) D0-D15
+static unsigned decodeRestrictedDm(uint32_t insn, ElemSize esize) {
+  switch (esize) {
+  case ESize16:
+    return insn & 7;
+  case ESize32:
+    return insn & 0xF;
+  default:
+    assert(0 && "Unreachable code!");
+    return 0;
+  }
+}
+
+// A8.6.339 VMUL, VMULL (by scalar)
+// ESize16 => index = Inst{5:3} (M:Vm<3>) D0-D7
+// ESize32 => index = Inst{5}   (M)       D0-D15
+static unsigned decodeRestrictedDmIndex(uint32_t insn, ElemSize esize) {
+  switch (esize) {
+  case ESize16:
+    return (((insn >> 5) & 1) << 1) | ((insn >> 3) & 1);
+  case ESize32:
+    return (insn >> 5) & 1;
+  default:
+    assert(0 && "Unreachable code!");
+    return 0;
+  }
+}
+
+// A8.6.296 VCVT (between floating-point and fixed-point, Advanced SIMD)
+// (64 - <fbits>) is encoded as imm6, i.e., Inst{21-16}.
+static unsigned decodeVCVTFractionBits(uint32_t insn) {
+  return 64 - ((insn >> 16) & 0x3F);
+}
+
+// A8.6.302 VDUP (scalar)
+// ESize8  => index = Inst{19-17}
+// ESize16 => index = Inst{19-18}
+// ESize32 => index = Inst{19}
+static unsigned decodeNVLaneDupIndex(uint32_t insn, ElemSize esize) {
+  switch (esize) {
+  case ESize8:
+    return (insn >> 17) & 7;
+  case ESize16:
+    return (insn >> 18) & 3;
+  case ESize32:
+    return (insn >> 19) & 1;
+  default:
+    assert(0 && "Unspecified element size!");
+    return 0;
+  }
+}
+
+// A8.6.328 VMOV (ARM core register to scalar)
+// A8.6.329 VMOV (scalar to ARM core register)
+// ESize8  => index = Inst{21:6-5}
+// ESize16 => index = Inst{21:6}
+// ESize32 => index = Inst{21}
+static unsigned decodeNVLaneOpIndex(uint32_t insn, ElemSize esize) {
+  switch (esize) {
+  case ESize8:
+    return ((insn >> 21) & 1) << 2 | ((insn >> 5) & 3);
+  case ESize16:
+    return ((insn >> 21) & 1) << 1 | ((insn >> 6) & 1);
+  case ESize32:
+    return ((insn >> 21) & 1);
+  default:
+    assert(0 && "Unspecified element size!");
+    return 0;
+  }
+}
+
+// Imm6 = Inst{21-16}, L = Inst{7}
+//
+// LeftShift == true (A8.6.367 VQSHL, A8.6.387 VSLI):
+// case L:imm6 of
+//   '0001xxx' => esize = 8; shift_amount = imm6 - 8
+//   '001xxxx' => esize = 16; shift_amount = imm6 - 16
+//   '01xxxxx' => esize = 32; shift_amount = imm6 - 32
+//   '1xxxxxx' => esize = 64; shift_amount = imm6
+//
+// LeftShift == false (A8.6.376 VRSHR, A8.6.368 VQSHRN):
+// case L:imm6 of
+//   '0001xxx' => esize = 8; shift_amount = 16 - imm6
+//   '001xxxx' => esize = 16; shift_amount = 32 - imm6
+//   '01xxxxx' => esize = 32; shift_amount = 64 - imm6
+//   '1xxxxxx' => esize = 64; shift_amount = 64 - imm6
+//
+static unsigned decodeNVSAmt(uint32_t insn, bool LeftShift) {
+  ElemSize esize = ESizeNA;
+  unsigned L = (insn >> 7) & 1;
+  unsigned imm6 = (insn >> 16) & 0x3F;
+  if (L == 0) {
+    if (imm6 >> 3 == 1)
+      esize = ESize8;
+    else if (imm6 >> 4 == 1)
+      esize = ESize16;
+    else if (imm6 >> 5 == 1)
+      esize = ESize32;
+    else
+      assert(0 && "Wrong encoding of Inst{7:21-16}!");
+  } else
+    esize = ESize64;
+
+  if (LeftShift)
+    return esize == ESize64 ? imm6 : (imm6 - esize);
+  else
+    return esize == ESize64 ? (esize - imm6) : (2*esize - imm6);
+}
+
+// A8.6.305 VEXT
+// Imm4 = Inst{11-8}
+static unsigned decodeN3VImm(uint32_t insn) {
+  return (insn >> 8) & 0xF;
+}
+
+// VLD*
+//   D[d] D[d2] ... Rn [TIED_TO Rn] align [Rm]
+// VLD*LN*
+//   D[d] D[d2] ... Rn [TIED_TO Rn] align [Rm] TIED_TO ... imm(idx)
+// VST*
+//   Rn [TIED_TO Rn] align [Rm] D[d] D[d2] ...
+// VST*LN*
+//   Rn [TIED_TO Rn] align [Rm] D[d] D[d2] ... [imm(idx)]
+//
+// Correctly set VLD*/VST*'s TIED_TO GPR, as the asm printer needs it.
+static bool DisassembleNLdSt0(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, bool Store, bool DblSpaced) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  // At least one DPR register plus addressing mode #6.
+  assert(NumOps >= 3 && "Expect >= 3 operands");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // We have homogeneous NEON registers for Load/Store.
+  unsigned RegClass = 0;
+
+  // Double-spaced registers have increments of 2.
+  unsigned Inc = DblSpaced ? 2 : 1;
+
+  unsigned Rn = decodeRn(insn);
+  unsigned Rm = decodeRm(insn);
+  unsigned Rd = decodeNEONRd(insn);
+
+  // A7.7.1 Advanced SIMD addressing mode.
+  bool WB = Rm != 15;
+
+  // LLVM Addressing Mode #6.
+  unsigned RmEnum = 0;
+  if (WB && Rm != 13)
+    RmEnum = getRegisterEnum(ARM::GPRRegClassID, Rm);
+
+  if (Store) {
+    // Consume possible WB, AddrMode6, possible increment reg, the DPR/QPR's,
+    // then possible lane index.
+    assert(OpIdx < NumOps && OpInfo[0].RegClass == ARM::GPRRegClassID &&
+           "Reg operand expected");
+
+    if (WB) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         Rn)));
+      ++OpIdx;
+    }
+
+    assert((OpIdx+1) < NumOps && OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           OpInfo[OpIdx + 1].RegClass == 0 && "Addrmode #6 Operands expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       Rn)));
+    MI.addOperand(MCOperand::CreateImm(0)); // Alignment ignored?
+    OpIdx += 2;
+
+    if (WB) {
+      MI.addOperand(MCOperand::CreateReg(RmEnum));
+      ++OpIdx;
+    }
+
+    assert(OpIdx < NumOps &&
+           (OpInfo[OpIdx].RegClass == ARM::DPRRegClassID ||
+            OpInfo[OpIdx].RegClass == ARM::QPRRegClassID) &&
+           "Reg operand expected");
+
+    RegClass = OpInfo[OpIdx].RegClass;
+    while (OpIdx < NumOps && OpInfo[OpIdx].RegClass == RegClass) {
+      if (Opcode >= ARM::VST1q16 && Opcode <= ARM::VST1q8)
+        MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClass,Rd,true)));
+      else
+        MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClass,Rd)));
+      Rd += Inc;
+      ++OpIdx;
+    }
+
+    // Handle possible lane index.
+    if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+        && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+      MI.addOperand(MCOperand::CreateImm(decodeLaneIndex(insn)));
+      ++OpIdx;
+    }
+
+  } else {
+    // Consume the DPR/QPR's, possible WB, AddrMode6, possible incrment reg,
+    // possible TIED_TO DPR/QPR's (ignored), then possible lane index.
+    RegClass = OpInfo[0].RegClass;
+
+    while (OpIdx < NumOps && OpInfo[OpIdx].RegClass == RegClass) {
+      if (Opcode >= ARM::VLD1q16 && Opcode <= ARM::VLD1q8)
+        MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClass,Rd,true)));
+      else
+        MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClass,Rd)));
+      Rd += Inc;
+      ++OpIdx;
+    }
+
+    if (WB) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         Rn)));
+      ++OpIdx;
+    }
+
+    assert((OpIdx+1) < NumOps && OpInfo[OpIdx].RegClass == ARM::GPRRegClassID &&
+           OpInfo[OpIdx + 1].RegClass == 0 && "Addrmode #6 Operands expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       Rn)));
+    MI.addOperand(MCOperand::CreateImm(0)); // Alignment ignored?
+    OpIdx += 2;
+
+    if (WB) {
+      MI.addOperand(MCOperand::CreateReg(RmEnum));
+      ++OpIdx;
+    }
+
+    while (OpIdx < NumOps && OpInfo[OpIdx].RegClass == RegClass) {
+      assert(TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1 &&
+             "Tied to operand expected");
+      MI.addOperand(MCOperand::CreateReg(0));
+      ++OpIdx;
+    }
+
+    // Handle possible lane index.
+    if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+        && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+      MI.addOperand(MCOperand::CreateImm(decodeLaneIndex(insn)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+// A7.7
+// If L (Inst{21}) == 0, store instructions.
+// Find out about double-spaced-ness of the Opcode and pass it on to
+// DisassembleNLdSt0().
+static bool DisassembleNLdSt(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const StringRef Name = ARMInsts[Opcode].Name;
+  bool DblSpaced = false;
+
+  if (Name.find("LN") != std::string::npos) {
+    // To one lane instructions.
+    // See, for example, 8.6.317 VLD4 (single 4-element structure to one lane).
+
+    // <size> == 16 && Inst{5} == 1 --> DblSpaced = true
+    if (Name.endswith("16") || Name.endswith("16_UPD"))
+      DblSpaced = slice(insn, 5, 5) == 1;
+
+    // <size> == 32 && Inst{6} == 1 --> DblSpaced = true
+    if (Name.endswith("32") || Name.endswith("32_UPD"))
+      DblSpaced = slice(insn, 6, 6) == 1;
+
+  } else {
+    // Multiple n-element structures with type encoded as Inst{11-8}.
+    // See, for example, A8.6.316 VLD4 (multiple 4-element structures).
+
+    // n == 2 && type == 0b1001 -> DblSpaced = true
+    if (Name.startswith("VST2") || Name.startswith("VLD2"))
+      DblSpaced = slice(insn, 11, 8) == 9;
+    
+    // n == 3 && type == 0b0101 -> DblSpaced = true
+    if (Name.startswith("VST3") || Name.startswith("VLD3"))
+      DblSpaced = slice(insn, 11, 8) == 5;
+    
+    // n == 4 && type == 0b0001 -> DblSpaced = true
+    if (Name.startswith("VST4") || Name.startswith("VLD4"))
+      DblSpaced = slice(insn, 11, 8) == 1;
+    
+  }
+  return DisassembleNLdSt0(MI, Opcode, insn, NumOps, NumOpsAdded,
+                           slice(insn, 21, 21) == 0, DblSpaced);
+}
+
+// VMOV (immediate)
+//   Qd/Dd imm
+static bool DisassembleN1RegModImmFrm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumOps >= 2 &&
+         (OpInfo[0].RegClass == ARM::DPRRegClassID ||
+          OpInfo[0].RegClass == ARM::QPRRegClassID) &&
+         (OpInfo[1].RegClass == 0) &&
+         "Expect 1 reg operand followed by 1 imm operand");
+
+  // Qd/Dd = Inst{22:15-12} => NEON Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[0].RegClass,
+                                                     decodeNEONRd(insn))));
+
+  ElemSize esize = ESizeNA;
+  switch (Opcode) {
+  case ARM::VMOVv8i8:
+  case ARM::VMOVv16i8:
+    esize = ESize8;
+    break;
+  case ARM::VMOVv4i16:
+  case ARM::VMOVv8i16:
+    esize = ESize16;
+    break;
+  case ARM::VMOVv2i32:
+  case ARM::VMOVv4i32:
+    esize = ESize32;
+    break;
+  case ARM::VMOVv1i64:
+  case ARM::VMOVv2i64:
+    esize = ESize64;
+  default:
+    assert(0 && "Unreachable code!");
+    return false;
+  }
+
+  // One register and a modified immediate value.
+  // Add the imm operand.
+  MI.addOperand(MCOperand::CreateImm(decodeN1VImm(insn, esize)));
+
+  NumOpsAdded = 2;
+  return true;
+}
+
+namespace {
+enum N2VFlag {
+  N2V_None,
+  N2V_VectorDupLane,
+  N2V_VectorConvert_Between_Float_Fixed
+};
+} // End of unnamed namespace
+
+// Vector Convert [between floating-point and fixed-point]
+//   Qd/Dd Qm/Dm [fbits]
+//
+// Vector Duplicate Lane (from scalar to all elements) Instructions.
+// VDUPLN16d, VDUPLN16q, VDUPLN32d, VDUPLN32q, VDUPLN8d, VDUPLN8q:
+//   Qd/Dd Dm index
+//
+// Vector Move Long:
+//   Qd Dm
+// 
+// Vector Move Narrow:
+//   Dd Qm
+//
+// Others
+static bool DisassembleNVdVmOptImm(MCInst &MI, unsigned Opc, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, N2VFlag Flag = N2V_None) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opc];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumOps >= 2 &&
+         (OpInfo[0].RegClass == ARM::DPRRegClassID ||
+          OpInfo[0].RegClass == ARM::QPRRegClassID) &&
+         (OpInfo[1].RegClass == ARM::DPRRegClassID ||
+          OpInfo[1].RegClass == ARM::QPRRegClassID) &&
+         "Expect >= 2 operands and first 2 as reg operands");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  ElemSize esize = ESizeNA;
+  if (Flag == N2V_VectorDupLane) {
+    // VDUPLN has its index embedded.  Its size can be inferred from the Opcode.
+    assert(Opc >= ARM::VDUPLN16d && Opc <= ARM::VDUPLN8q &&
+           "Unexpected Opcode");
+    esize = (Opc == ARM::VDUPLN8d || Opc == ARM::VDUPLN8q) ? ESize8
+       : ((Opc == ARM::VDUPLN16d || Opc == ARM::VDUPLN16q) ? ESize16
+                                                           : ESize32);
+  }
+
+  // Qd/Dd = Inst{22:15-12} => NEON Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                                     decodeNEONRd(insn))));
+  ++OpIdx;
+
+  // VPADAL...
+  if (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1) {
+    // TIED_TO operand.
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  // Dm = Inst{5:3-0} => NEON Rm
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                                     decodeNEONRm(insn))));
+  ++OpIdx;
+
+  // VZIP and others have two TIED_TO reg operands.
+  int Idx;
+  while (OpIdx < NumOps &&
+         (Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+    // Add TIED_TO operand.
+    MI.addOperand(MI.getOperand(Idx));
+    ++OpIdx;
+  }
+
+  // Add the imm operand, if required.
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+      && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+
+    unsigned imm = 0xFFFFFFFF;
+
+    if (Flag == N2V_VectorDupLane)
+      imm = decodeNVLaneDupIndex(insn, esize);
+    if (Flag == N2V_VectorConvert_Between_Float_Fixed)
+      imm = decodeVCVTFractionBits(insn);
+
+    assert(imm != 0xFFFFFFFF && "Internal error");
+    MI.addOperand(MCOperand::CreateImm(imm));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+static bool DisassembleN2RegFrm(MCInst &MI, unsigned Opc, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVmOptImm(MI, Opc, insn, NumOps, NumOpsAdded);
+}
+static bool DisassembleNVCVTFrm(MCInst &MI, unsigned Opc, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVmOptImm(MI, Opc, insn, NumOps, NumOpsAdded,
+                                N2V_VectorConvert_Between_Float_Fixed);
+}
+static bool DisassembleNVecDupLnFrm(MCInst &MI, unsigned Opc, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVmOptImm(MI, Opc, insn, NumOps, NumOpsAdded,
+                                N2V_VectorDupLane);
+}
+
+// Vector Shift [Accumulate] Instructions.
+// Qd/Dd [Qd/Dd (TIED_TO)] Qm/Dm ShiftAmt
+//
+// Vector Shift Left Long (with maximum shift count) Instructions.
+// VSHLLi16, VSHLLi32, VSHLLi8: Qd Dm imm (== size)
+//
+static bool DisassembleNVectorShift(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, bool LeftShift) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumOps >= 3 &&
+         (OpInfo[0].RegClass == ARM::DPRRegClassID ||
+          OpInfo[0].RegClass == ARM::QPRRegClassID) &&
+         (OpInfo[1].RegClass == ARM::DPRRegClassID ||
+          OpInfo[1].RegClass == ARM::QPRRegClassID) &&
+         "Expect >= 3 operands and first 2 as reg operands");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // Qd/Dd = Inst{22:15-12} => NEON Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                                     decodeNEONRd(insn))));
+  ++OpIdx;
+
+  if (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1) {
+    // TIED_TO operand.
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  assert((OpInfo[OpIdx].RegClass == ARM::DPRRegClassID ||
+          OpInfo[OpIdx].RegClass == ARM::QPRRegClassID) &&
+         "Reg operand expected");
+
+  // Qm/Dm = Inst{5:3-0} => NEON Rm
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                                     decodeNEONRm(insn))));
+  ++OpIdx;
+
+  assert(OpInfo[OpIdx].RegClass == 0 && "Imm operand expected");
+
+  // Add the imm operand.
+  
+  // VSHLL has maximum shift count as the imm, inferred from its size.
+  unsigned Imm;
+  switch (Opcode) {
+  default:
+    Imm = decodeNVSAmt(insn, LeftShift);
+    break;
+  case ARM::VSHLLi8:
+    Imm = 8;
+    break;
+  case ARM::VSHLLi16:
+    Imm = 16;
+    break;
+  case ARM::VSHLLi32:
+    Imm = 32;
+    break;
+  }
+  MI.addOperand(MCOperand::CreateImm(Imm));
+  ++OpIdx;
+
+  return true;
+}
+
+// Left shift instructions.
+static bool DisassembleN2RegVecShLFrm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVectorShift(MI, Opcode, insn, NumOps, NumOpsAdded, true);
+}
+// Right shift instructions have different shift amount interpretation.
+static bool DisassembleN2RegVecShRFrm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVectorShift(MI, Opcode, insn, NumOps, NumOpsAdded, false);
+}
+
+namespace {
+enum N3VFlag {
+  N3V_None,
+  N3V_VectorExtract,
+  N3V_VectorShift,
+  N3V_Multiply_By_Scalar
+};
+} // End of unnamed namespace
+
+// NEON Three Register Instructions with Optional Immediate Operand
+//
+// Vector Extract Instructions.
+// Qd/Dd Qn/Dn Qm/Dm imm4
+//
+// Vector Shift (Register) Instructions.
+// Qd/Dd Qm/Dm Qn/Dn (notice the order of m, n)
+//
+// Vector Multiply [Accumulate/Subtract] [Long] By Scalar Instructions.
+// Qd/Dd Qn/Dn RestrictedDm index
+//
+// Others
+static bool DisassembleNVdVnVmOptImm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, N3VFlag Flag = N3V_None) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  // No checking for OpInfo[2] because of MOVDneon/MOVQ with only two regs.
+  assert(NumOps >= 3 &&
+         (OpInfo[0].RegClass == ARM::DPRRegClassID ||
+          OpInfo[0].RegClass == ARM::QPRRegClassID) &&
+         (OpInfo[1].RegClass == ARM::DPRRegClassID ||
+          OpInfo[1].RegClass == ARM::QPRRegClassID) &&
+         "Expect >= 3 operands and first 2 as reg operands");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  bool VdVnVm = Flag == N3V_VectorShift ? false : true;
+  bool IsImm4 = Flag == N3V_VectorExtract ? true : false;
+  bool IsDmRestricted = Flag == N3V_Multiply_By_Scalar ? true : false;
+  ElemSize esize = ESizeNA;
+  if (Flag == N3V_Multiply_By_Scalar) {
+    unsigned size = (insn >> 20) & 3;
+    if (size == 1) esize = ESize16;
+    if (size == 2) esize = ESize32;
+    assert (esize == ESize16 || esize == ESize32);
+  }
+
+  // Qd/Dd = Inst{22:15-12} => NEON Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                                     decodeNEONRd(insn))));
+  ++OpIdx;
+
+  // VABA, VABAL, VBSLd, VBSLq, ...
+  if (TID.getOperandConstraint(OpIdx, TOI::TIED_TO) != -1) {
+    // TIED_TO operand.
+    MI.addOperand(MCOperand::CreateReg(0));
+    ++OpIdx;
+  }
+
+  // Dn = Inst{7:19-16} => NEON Rn
+  // or
+  // Dm = Inst{5:3-0} => NEON Rm
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(OpInfo[OpIdx].RegClass,
+                                  VdVnVm ? decodeNEONRn(insn)
+                                         : decodeNEONRm(insn))));
+  ++OpIdx;
+
+  // Special case handling for VMOVDneon and VMOVQ because they are marked as
+  // N3RegFrm.
+  if (Opcode == ARM::VMOVDneon || Opcode == ARM::VMOVQ)
+    return true;
+  
+  // Dm = Inst{5:3-0} => NEON Rm
+  // or
+  // Dm is restricted to D0-D7 if size is 16, D0-D15 otherwise
+  // or
+  // Dn = Inst{7:19-16} => NEON Rn
+  unsigned m = VdVnVm ? (IsDmRestricted ? decodeRestrictedDm(insn, esize)
+                                        : decodeNEONRm(insn))
+                      : decodeNEONRn(insn);
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(OpInfo[OpIdx].RegClass, m)));
+  ++OpIdx;
+
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+      && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // Add the imm operand.
+    unsigned Imm = 0;
+    if (IsImm4)
+      Imm = decodeN3VImm(insn);
+    else if (IsDmRestricted)
+      Imm = decodeRestrictedDmIndex(insn, esize);
+    else {
+      assert(0 && "Internal error: unreachable code!");
+      return false;
+    }
+
+    MI.addOperand(MCOperand::CreateImm(Imm));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+static bool DisassembleN3RegFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVnVmOptImm(MI, Opcode, insn, NumOps, NumOpsAdded);
+}
+static bool DisassembleN3RegVecShFrm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVnVmOptImm(MI, Opcode, insn, NumOps, NumOpsAdded,
+                                  N3V_VectorShift);
+}
+static bool DisassembleNVecExtractFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVnVmOptImm(MI, Opcode, insn, NumOps, NumOpsAdded,
+                                  N3V_VectorExtract);
+}
+static bool DisassembleNVecMulScalarFrm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  return DisassembleNVdVnVmOptImm(MI, Opcode, insn, NumOps, NumOpsAdded,
+                                  N3V_Multiply_By_Scalar);
+}
+
+// Vector Table Lookup
+//
+// VTBL1, VTBX1: Dd [Dd(TIED_TO)] Dn Dm
+// VTBL2, VTBX2: Dd [Dd(TIED_TO)] Dn Dn+1 Dm
+// VTBL3, VTBX3: Dd [Dd(TIED_TO)] Dn Dn+1 Dn+2 Dm
+// VTBL4, VTBX4: Dd [Dd(TIED_TO)] Dn Dn+1 Dn+2 Dn+3 Dm
+static bool DisassembleNVTBLFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::DPRRegClassID &&
+         OpInfo[1].RegClass == ARM::DPRRegClassID &&
+         OpInfo[2].RegClass == ARM::DPRRegClassID &&
+         "Expect >= 3 operands and first 3 as reg operands");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned Rn = decodeNEONRn(insn);
+
+  // {Dn} encoded as len = 0b00
+  // {Dn Dn+1} encoded as len = 0b01
+  // {Dn Dn+1 Dn+2 } encoded as len = 0b10
+  // {Dn Dn+1 Dn+2 Dn+3} encoded as len = 0b11
+  unsigned Len = slice(insn, 9, 8) + 1;
+
+  // Dd (the destination vector)
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::DPRRegClassID,
+                                                     decodeNEONRd(insn))));
+  ++OpIdx;
+
+  // Process tied_to operand constraint.
+  int Idx;
+  if ((Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+    MI.addOperand(MI.getOperand(Idx));
+    ++OpIdx;
+  }
+
+  // Do the <list> now.
+  for (unsigned i = 0; i < Len; ++i) {
+    assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::DPRRegClassID &&
+           "Reg operand expected");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::DPRRegClassID,
+                                                       Rn + i)));
+    ++OpIdx;
+  }
+
+  // Dm (the index vector)
+  assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::DPRRegClassID &&
+         "Reg operand (index vector) expected");
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::DPRRegClassID,
+                                                     decodeNEONRm(insn))));
+  ++OpIdx;
+
+  return true;
+}
+
+static bool DisassembleNEONFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+  assert(0 && "Unreachable code!");
+  return false;
+}
+
+// Vector Get Lane (move scalar to ARM core register) Instructions.
+// VGETLNi32, VGETLNs16, VGETLNs8, VGETLNu16, VGETLNu8: Rt Dn index
+static bool DisassembleNEONGetLnFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumDefs == 1 && NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == ARM::DPRRegClassID &&
+         OpInfo[2].RegClass == 0 &&
+         "Expect >= 3 operands with one dst operand");
+
+  ElemSize esize =
+    Opcode == ARM::VGETLNi32 ? ESize32
+      : ((Opcode == ARM::VGETLNs16 || Opcode == ARM::VGETLNu16) ? ESize16
+                                                                : ESize32);
+
+  // Rt = Inst{15-12} => ARM Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+
+  // Dn = Inst{7:19-16} => NEON Rn
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::DPRRegClassID,
+                                                     decodeNEONRn(insn))));
+
+  MI.addOperand(MCOperand::CreateImm(decodeNVLaneOpIndex(insn, esize)));
+
+  NumOpsAdded = 3;
+  return true;
+}
+
+// Vector Set Lane (move ARM core register to scalar) Instructions.
+// VSETLNi16, VSETLNi32, VSETLNi8: Dd Dd (TIED_TO) Rt index
+static bool DisassembleNEONSetLnFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  unsigned short NumDefs = TID.getNumDefs();
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+
+  assert(NumDefs == 1 && NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::DPRRegClassID &&
+         OpInfo[1].RegClass == ARM::DPRRegClassID &&
+         TID.getOperandConstraint(1, TOI::TIED_TO) != -1 &&
+         OpInfo[2].RegClass == ARM::GPRRegClassID &&
+         OpInfo[3].RegClass == 0 &&
+         "Expect >= 3 operands with one dst operand");
+
+  ElemSize esize =
+    Opcode == ARM::VSETLNi8 ? ESize8
+                            : (Opcode == ARM::VSETLNi16 ? ESize16
+                                                        : ESize32);
+
+  // Dd = Inst{7:19-16} => NEON Rn
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::DPRRegClassID,
+                                                     decodeNEONRn(insn))));
+
+  // TIED_TO operand.
+  MI.addOperand(MCOperand::CreateReg(0));
+
+  // Rt = Inst{15-12} => ARM Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+
+  MI.addOperand(MCOperand::CreateImm(decodeNVLaneOpIndex(insn, esize)));
+
+  NumOpsAdded = 4;
+  return true;
+}
+
+// Vector Duplicate Instructions (from ARM core register to all elements).
+// VDUP8d, VDUP16d, VDUP32d, VDUP8q, VDUP16q, VDUP32q: Qd/Dd Rt
+static bool DisassembleNEONDupFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 2 &&
+         (OpInfo[0].RegClass == ARM::DPRRegClassID ||
+          OpInfo[0].RegClass == ARM::QPRRegClassID) &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 2 operands and first 2 as reg operand");
+
+  unsigned RegClass = OpInfo[0].RegClass;
+
+  // Qd/Dd = Inst{7:19-16} => NEON Rn
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(RegClass,
+                                                     decodeNEONRn(insn))));
+
+  // Rt = Inst{15-12} => ARM Rd
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+
+  NumOpsAdded = 2;
+  return true;
+}
+
+// A8.6.41 DMB
+// A8.6.42 DSB
+// A8.6.49 ISB
+static inline bool MemBarrierInstr(uint32_t insn) {
+  unsigned op7_4 = slice(insn, 7, 4);
+  if (slice(insn, 31, 20) == 0xf57 && (op7_4 >= 4 && op7_4 <= 6))
+    return true;
+
+  return false;
+}
+
+static inline bool PreLoadOpcode(unsigned Opcode) {
+  switch(Opcode) {
+  case ARM::PLDi:  case ARM::PLDr:
+  case ARM::PLDWi: case ARM::PLDWr:
+  case ARM::PLIi:  case ARM::PLIr:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static bool DisassemblePreLoadFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  // Preload Data/Instruction requires either 2 or 4 operands.
+  // PLDi, PLDWi, PLIi:                Rn [+/-]imm12 add = (U == '1')
+  // PLDr[a|m], PLDWr[a|m], PLIr[a|m]: Rn Rm addrmode2_opc
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+
+  if (Opcode == ARM::PLDi || Opcode == ARM::PLDWi || Opcode == ARM::PLIi) {
+    unsigned Imm12 = slice(insn, 11, 0);
+    bool Negative = getUBit(insn) == 0;
+    int Offset = Negative ? -1 - Imm12 : 1 * Imm12;
+    MI.addOperand(MCOperand::CreateImm(Offset));
+    NumOpsAdded = 2;
+  } else {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+
+    ARM_AM::AddrOpc AddrOpcode = getUBit(insn) ? ARM_AM::add : ARM_AM::sub;
+
+    // Inst{6-5} encodes the shift opcode.
+    ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 6, 5));
+    // Inst{11-7} encodes the imm5 shift amount.
+    unsigned ShImm = slice(insn, 11, 7);
+
+    // A8.4.1.  Possible rrx or shift amount of 32...
+    getImmShiftSE(ShOp, ShImm);
+    MI.addOperand(MCOperand::CreateImm(
+                    ARM_AM::getAM2Opc(AddrOpcode, ShImm, ShOp)));
+    NumOpsAdded = 3;
+  }
+
+  return true;
+}
+
+static bool DisassembleMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  if (MemBarrierInstr(insn))
+    return true;
+
+  switch (Opcode) {
+  case ARM::CLREX:
+  case ARM::NOP:
+  case ARM::TRAP:
+  case ARM::YIELD:
+  case ARM::WFE:
+  case ARM::WFI:
+  case ARM::SEV:
+  case ARM::SETENDBE:
+  case ARM::SETENDLE:
+    return true;
+  default:
+    break;
+  }
+
+  // CPS has a singleton $opt operand that contains the following information:
+  // opt{4-0} = mode from Inst{4-0}
+  // opt{5} = changemode from Inst{17}
+  // opt{8-6} = AIF from Inst{8-6}
+  // opt{10-9} = imod from Inst{19-18} with 0b10 as enable and 0b11 as disable
+  if (Opcode == ARM::CPS) {
+    unsigned Option = slice(insn, 4, 0) | slice(insn, 17, 17) << 5 |
+      slice(insn, 8, 6) << 6 | slice(insn, 19, 18) << 9;
+    MI.addOperand(MCOperand::CreateImm(Option));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // DBG has its option specified in Inst{3-0}.
+  if (Opcode == ARM::DBG) {
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 3, 0)));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // BKPT takes an imm32 val equal to ZeroExtend(Inst{19-8:3-0}).
+  if (Opcode == ARM::BKPT) {
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 8) << 4 |
+                                       slice(insn, 3, 0)));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  if (PreLoadOpcode(Opcode))
+    return DisassemblePreLoadFrm(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  assert(0 && "Unexpected misc instruction!");
+  return false;
+}
+
+static bool DisassembleThumbMiscFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO) {
+
+  assert(0 && "Unexpected thumb misc. instruction!");
+  return false;
+}
+
+/// FuncPtrs - FuncPtrs maps ARMFormat to its corresponding DisassembleFP.
+/// We divide the disassembly task into different categories, with each one
+/// corresponding to a specific instruction encoding format.  There could be
+/// exceptions when handling a specific format, and that is why the Opcode is
+/// also present in the function prototype.
+static const DisassembleFP FuncPtrs[] = {
+  &DisassemblePseudo,
+  &DisassembleMulFrm,
+  &DisassembleBrFrm,
+  &DisassembleBrMiscFrm,
+  &DisassembleDPFrm,
+  &DisassembleDPSoRegFrm,
+  &DisassembleLdFrm,
+  &DisassembleStFrm,
+  &DisassembleLdMiscFrm,
+  &DisassembleStMiscFrm,
+  &DisassembleLdStMulFrm,
+  &DisassembleLdStExFrm,
+  &DisassembleArithMiscFrm,
+  &DisassembleExtFrm,
+  &DisassembleVFPUnaryFrm,
+  &DisassembleVFPBinaryFrm,
+  &DisassembleVFPConv1Frm,
+  &DisassembleVFPConv2Frm,
+  &DisassembleVFPConv3Frm,
+  &DisassembleVFPConv4Frm,
+  &DisassembleVFPConv5Frm,
+  &DisassembleVFPLdStFrm,
+  &DisassembleVFPLdStMulFrm,
+  &DisassembleVFPMiscFrm,
+  &DisassembleThumbFrm,
+  &DisassembleNEONFrm,
+  &DisassembleNEONGetLnFrm,
+  &DisassembleNEONSetLnFrm,
+  &DisassembleNEONDupFrm,
+  &DisassembleMiscFrm,
+  &DisassembleThumbMiscFrm,
+
+  // VLD and VST (including one lane) Instructions.
+  &DisassembleNLdSt,
+
+  // A7.4.6 One register and a modified immediate value
+  // 1-Register Instructions with imm.
+  // LLVM only defines VMOVv instructions.
+  &DisassembleN1RegModImmFrm,
+
+  // 2-Register Instructions with no imm.
+  &DisassembleN2RegFrm,
+
+  // 2-Register Instructions with imm (vector convert float/fixed point).
+  &DisassembleNVCVTFrm,
+
+  // 2-Register Instructions with imm (vector dup lane).
+  &DisassembleNVecDupLnFrm,
+
+  // Vector Shift Left Instructions.
+  &DisassembleN2RegVecShLFrm,
+
+  // Vector Shift Righ Instructions, which has different interpretation of the
+  // shift amount from the imm6 field.
+  &DisassembleN2RegVecShRFrm,
+
+  // 3-Register Data-Processing Instructions.
+  &DisassembleN3RegFrm,
+
+  // Vector Shift (Register) Instructions.
+  // D:Vd M:Vm N:Vn (notice that M:Vm is the first operand)
+  &DisassembleN3RegVecShFrm,
+
+  // Vector Extract Instructions.
+  &DisassembleNVecExtractFrm,
+
+  // Vector [Saturating Rounding Doubling] Multiply [Accumulate/Subtract] [Long]
+  // By Scalar Instructions.
+  &DisassembleNVecMulScalarFrm,
+
+  // Vector Table Lookup uses byte indexes in a control vector to look up byte
+  // values in a table and generate a new vector.
+  &DisassembleNVTBLFrm,
+
+  NULL
+};
+
+/// Algorithms - Algorithms stores a map from Format to ARMAlgorithm*.
+static std::vector<ARMAlgorithm*> Algorithms;
+
+/// GetInstance - GetInstance returns an instance of ARMAlgorithm given the
+/// encoding Format.  API clients should not free up the returned instance.
+ARMAlgorithm *ARMAlgorithm::GetInstance(ARMFormat Format) {
+  /// Init the first time.
+  if (Algorithms.size() == 0) {
+    Algorithms.resize(array_lengthof(FuncPtrs));
+    for (unsigned i = 0, num = array_lengthof(FuncPtrs); i < num; ++i)
+      if (FuncPtrs[i])
+        Algorithms[i] = new ARMAlgorithm(FuncPtrs[i]);
+      else
+        Algorithms[i] = NULL;
+  }
+  return Algorithms[Format];
+}
+
+
+/// BuildIt - BuildIt performs the build step for this ARM Basic MC Builder.
+/// The general idea is to set the Opcode for the MCInst, followed by adding
+/// the appropriate MCOperands to the MCInst.  ARM Basic MC Builder delegates
+/// to the Algo (ARM Disassemble Algorithm) object to perform Format-specific
+/// disassembly, followed by class method TryPredicateAndSBitModifier() to do
+/// PredicateOperand and OptionalDefOperand which follow the Dst/Src Operands.
+bool ARMBasicMCBuilder::BuildIt(MCInst &MI, uint32_t insn) {
+  // Stage 1 sets the Opcode.
+  MI.setOpcode(Opcode);
+  // If the number of operands is zero, we're done!
+  if (NumOps == 0)
+    return true;
+
+  // Stage 2 calls the ARM Disassembly Algorithm to build the operand list.
+  unsigned NumOpsAdded = 0;
+  bool OK = Algo.Solve(MI, Opcode, insn, NumOps, NumOpsAdded, this);
+
+  if (!OK) return false;
+  if (NumOpsAdded >= NumOps)
+    return true;
+
+  // Stage 3 deals with operands unaccounted for after stage 2 is finished.
+  // FIXME: Should this be done selectively?
+  return TryPredicateAndSBitModifier(MI, Opcode, insn, NumOps - NumOpsAdded);
+}
+
+bool ARMBasicMCBuilder::TryPredicateAndSBitModifier(MCInst& MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOpsRemaining) {
+
+  assert(NumOpsRemaining > 0 && "Invalid argument");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  const std::string &Name = ARMInsts[Opcode].Name;
+  unsigned Idx = MI.getNumOperands();
+
+  // First, we check whether this instr specifies the PredicateOperand through
+  // a pair of TargetOperandInfos with isPredicate() property.
+  if (NumOpsRemaining >= 2 &&
+      OpInfo[Idx].isPredicate() && OpInfo[Idx+1].isPredicate() &&
+      OpInfo[Idx].RegClass == 0 && OpInfo[Idx+1].RegClass == ARM::CCRRegClassID)
+  {
+    // If we are inside an IT block, get the IT condition bits maintained via
+    // ARMBasicMCBuilder::ITState[7:0], through ARMBasicMCBuilder::GetITCond().
+    // See also A2.5.2.
+    if (InITBlock())
+      MI.addOperand(MCOperand::CreateImm(GetITCond()));
+    else {
+      if (Name.length() > 1 && Name[0] == 't') {
+        // Thumb conditional branch instructions have their cond field embedded,
+        // like ARM.
+        //
+        // A8.6.16 B
+        if (Name == "t2Bcc")
+          MI.addOperand(MCOperand::CreateImm(slice(insn, 25, 22)));
+        else if (Name == "tBcc")
+          MI.addOperand(MCOperand::CreateImm(slice(insn, 11, 8)));
+        else
+          MI.addOperand(MCOperand::CreateImm(ARMCC::AL));
+      } else {
+        // ARM Instructions.  Check condition field.
+        int64_t CondVal = getCondField(insn);
+        if (CondVal == 0xF)
+          MI.addOperand(MCOperand::CreateImm(ARMCC::AL));
+        else
+          MI.addOperand(MCOperand::CreateImm(CondVal));
+      }
+    }
+    MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+    Idx += 2;
+    NumOpsRemaining -= 2;
+    if (NumOpsRemaining == 0)
+      return true;
+  }
+
+  // Next, if OptionalDefOperand exists, we check whether the 'S' bit is set.
+  if (OpInfo[Idx].isOptionalDef() && OpInfo[Idx].RegClass==ARM::CCRRegClassID) {
+    MI.addOperand(MCOperand::CreateReg(getSBit(insn) == 1 ? ARM::CPSR : 0));
+    --NumOpsRemaining;
+  }
+
+  if (NumOpsRemaining == 0)
+    return true;
+  else
+    return false;
+}
+
+/// RunBuildAfterHook - RunBuildAfterHook performs operations deemed necessary
+/// after BuildIt is finished.
+bool ARMBasicMCBuilder::RunBuildAfterHook(bool Status, MCInst &MI,
+    uint32_t insn) {
+
+  if (!SP) return Status;
+
+  if (Opcode == ARM::t2IT)
+    SP->InitIT(slice(insn, 7, 0));
+  else if (InITBlock())
+    SP->UpdateIT();
+
+  return Status;
+}
+
+/// CreateMCBuilder - Return an ARMBasicMCBuilder that can build up the MC
+/// infrastructure of an MCInst given the Opcode and Format of the instr.
+/// Return NULL if it fails to create/return a proper builder.  API clients
+/// are responsible for freeing up of the allocated memory.  Cacheing can be
+/// performed by the API clients to improve performance.
+ARMBasicMCBuilder *llvm::CreateMCBuilder(unsigned Opcode, ARMFormat Format) {
+
+  ARMAlgorithm *Algo = ARMAlgorithm::GetInstance(Format);
+  if (!Algo)
+    return NULL;
+
+  return new ARMBasicMCBuilder(Opcode, Format,
+                               ARMInsts[Opcode].getNumOperands(), *Algo);
+}

Added: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.h Fri Apr  2 17:27:38 2010
@@ -0,0 +1,280 @@
+//===- ARMDisassemblerCore.h - ARM disassembler helpers ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+//
+// The first part defines the enumeration type of ARM instruction format, which
+// specifies the encoding used by the instruction, as well as a helper function
+// to convert the enums to printable char strings.
+//
+// It also contains code to represent the concepts of Builder, Builder Factory,
+// as well as the Algorithm to solve the problem of disassembling an ARM instr.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ARMDISASSEMBLERCORE_H
+#define ARMDISASSEMBLERCORE_H
+
+#include "llvm/MC/MCInst.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "ARMInstrInfo.h"
+#include "ARMDisassembler.h"
+
+namespace llvm {
+
+class ARMUtils {
+public:
+  static const char *OpcodeName(unsigned Opcode);
+};
+
+/////////////////////////////////////////////////////
+//                                                 //
+//  Enums and Utilities for ARM Instruction Format //
+//                                                 //
+/////////////////////////////////////////////////////
+
+#define ARM_FORMATS                   \
+  ENTRY(ARM_FORMAT_PSEUDO,         0) \
+  ENTRY(ARM_FORMAT_MULFRM,         1) \
+  ENTRY(ARM_FORMAT_BRFRM,          2) \
+  ENTRY(ARM_FORMAT_BRMISCFRM,      3) \
+  ENTRY(ARM_FORMAT_DPFRM,          4) \
+  ENTRY(ARM_FORMAT_DPSOREGFRM,     5) \
+  ENTRY(ARM_FORMAT_LDFRM,          6) \
+  ENTRY(ARM_FORMAT_STFRM,          7) \
+  ENTRY(ARM_FORMAT_LDMISCFRM,      8) \
+  ENTRY(ARM_FORMAT_STMISCFRM,      9) \
+  ENTRY(ARM_FORMAT_LDSTMULFRM,    10) \
+  ENTRY(ARM_FORMAT_LDSTEXFRM,     11) \
+  ENTRY(ARM_FORMAT_ARITHMISCFRM,  12) \
+  ENTRY(ARM_FORMAT_EXTFRM,        13) \
+  ENTRY(ARM_FORMAT_VFPUNARYFRM,   14) \
+  ENTRY(ARM_FORMAT_VFPBINARYFRM,  15) \
+  ENTRY(ARM_FORMAT_VFPCONV1FRM,   16) \
+  ENTRY(ARM_FORMAT_VFPCONV2FRM,   17) \
+  ENTRY(ARM_FORMAT_VFPCONV3FRM,   18) \
+  ENTRY(ARM_FORMAT_VFPCONV4FRM,   19) \
+  ENTRY(ARM_FORMAT_VFPCONV5FRM,   20) \
+  ENTRY(ARM_FORMAT_VFPLDSTFRM,    21) \
+  ENTRY(ARM_FORMAT_VFPLDSTMULFRM, 22) \
+  ENTRY(ARM_FORMAT_VFPMISCFRM,    23) \
+  ENTRY(ARM_FORMAT_THUMBFRM,      24) \
+  ENTRY(ARM_FORMAT_NEONFRM,       25) \
+  ENTRY(ARM_FORMAT_NEONGETLNFRM,  26) \
+  ENTRY(ARM_FORMAT_NEONSETLNFRM,  27) \
+  ENTRY(ARM_FORMAT_NEONDUPFRM,    28) \
+  ENTRY(ARM_FORMAT_MISCFRM,       29) \
+  ENTRY(ARM_FORMAT_THUMBMISCFRM,  30) \
+  ENTRY(ARM_FORMAT_NLdSt,         31) \
+  ENTRY(ARM_FORMAT_N1RegModImm,   32) \
+  ENTRY(ARM_FORMAT_N2Reg,         33) \
+  ENTRY(ARM_FORMAT_NVCVT,         34) \
+  ENTRY(ARM_FORMAT_NVecDupLn,     35) \
+  ENTRY(ARM_FORMAT_N2RegVecShL,   36) \
+  ENTRY(ARM_FORMAT_N2RegVecShR,   37) \
+  ENTRY(ARM_FORMAT_N3Reg,         38) \
+  ENTRY(ARM_FORMAT_N3RegVecSh,    39) \
+  ENTRY(ARM_FORMAT_NVecExtract,   40) \
+  ENTRY(ARM_FORMAT_NVecMulScalar, 41) \
+  ENTRY(ARM_FORMAT_NVTBL,         42)
+
+// ARM instruction format specifies the encoding used by the instruction.
+#define ENTRY(n, v) n = v,
+typedef enum {
+  ARM_FORMATS
+  ARM_FORMAT_NA
+} ARMFormat;
+#undef ENTRY
+
+// Converts enum to const char*.
+static const inline char *stringForARMFormat(ARMFormat form) {
+#define ENTRY(n, v) case n: return #n;
+  switch(form) {
+    ARM_FORMATS
+  case ARM_FORMAT_NA:
+  default:
+    return "";
+  }
+#undef ENTRY
+}
+
+/// Expands on the enum definitions from ARMBaseInstrInfo.h.
+/// They are being used by the disassembler implementation.
+namespace ARMII {
+  enum {
+    NEONRegMask = 15,
+    GPRRegMask = 15,
+    NEON_RegRdShift = 12,
+    NEON_D_BitShift = 22,
+    NEON_RegRnShift = 16,
+    NEON_N_BitShift = 7,
+    NEON_RegRmShift = 0,
+    NEON_M_BitShift = 5
+  };
+}
+
+/// Utility function for extracting [From, To] bits from a uint32_t.
+static inline unsigned slice(uint32_t Bits, unsigned From, unsigned To) {
+  assert(From < 32 && To < 32 && From >= To);
+  return (Bits >> To) & ((1 << (From - To + 1)) - 1);
+}
+
+/// Utility function for setting [From, To] bits to Val for a uint32_t.
+static inline void setSlice(uint32_t &Bits, unsigned From, unsigned To,
+                            uint32_t Val) {
+  assert(From < 32 && To < 32 && From >= To);
+  uint32_t Mask = ((1 << (From - To + 1)) - 1);
+  Bits &= ~(Mask << To);
+  Bits |= (Val & Mask) << To;
+}
+
+/// Various utilities for checking the target specific flags.
+
+/// A unary data processing instruction doesn't have an Rn operand.
+static inline bool isUnaryDP(unsigned TSFlags) {
+  return (TSFlags & ARMII::UnaryDP);
+}
+
+/// This four-bit field describes the addressing mode used.
+/// See also ARMBaseInstrInfo.h.
+static inline unsigned getAddrMode(unsigned TSFlags) {
+  return (TSFlags & ARMII::AddrModeMask);
+}
+
+/// {IndexModePre, IndexModePost}
+/// Only valid for load and store ops.
+/// See also ARMBaseInstrInfo.h.
+static inline unsigned getIndexMode(unsigned TSFlags) {
+  return (TSFlags & ARMII::IndexModeMask) >> ARMII::IndexModeShift;
+}
+
+/// Pre-/post-indexed operations define an extra $base_wb in the OutOperandList.
+static inline bool isPrePostLdSt(unsigned TSFlags) {
+  return (TSFlags & ARMII::IndexModeMask) != 0;
+}
+
+// Forward declaration.
+class ARMBasicMCBuilder;
+
+// Builder Object is mostly ignored except in some Thumb disassemble functions.
+typedef ARMBasicMCBuilder *BO;
+
+/// DisassembleFP - DisassembleFP points to a function that disassembles an insn
+/// and builds the MCOperand list upon disassembly.  It returns false on failure
+/// or true on success.  The number of operands added is updated upon success.
+typedef bool (*DisassembleFP)(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO Builder);
+
+/// ARMAlgorithm - ARMAlgorithm implements the ARM/Thumb disassembly by solving
+/// the problem of building the MCOperands of an MCInst.  Construction of
+/// ARMAlgorithm requires passing in a function pointer with the DisassembleFP
+/// data type.
+class ARMAlgorithm {
+public:
+  /// GetInstance - GetInstance returns an instance of ARMAlgorithm given the
+  /// encoding Format.  API clients should not free up the returned instance.
+  static ARMAlgorithm *GetInstance(ARMFormat Format);
+
+  /// Return true if this algorithm successfully disassembles the instruction.
+  /// NumOpsAdded is updated to reflect the number of operands added by the
+  /// algorithm.  NumOpsAdded may be less than NumOps, in which case, there are
+  /// operands unaccounted for which need to be dealt with by the API client.
+  bool Solve(MCInst &MI, unsigned Opcode, uint32_t insn, unsigned short NumOps,
+      unsigned &NumOpsAdded, BO Builder) const {
+    if (Disassemble == NULL)
+      return false;
+
+    return (*Disassemble)(MI, Opcode, insn, NumOps, NumOpsAdded, Builder);
+  }
+
+private:
+  ARMAlgorithm(DisassembleFP fp) : Disassemble(fp) {}
+  ARMAlgorithm(ARMAlgorithm &AA) : Disassemble(AA.Disassemble) {}
+
+  virtual ~ARMAlgorithm() {}
+
+  DisassembleFP Disassemble;
+};
+
+/// ARMBasicMCBuilder - ARMBasicMCBuilder represents an ARM MCInst builder that
+/// knows how to build up the MCOperand list.
+class ARMBasicMCBuilder {
+  unsigned Opcode;
+  ARMFormat Format;
+  unsigned short NumOps;
+  const ARMAlgorithm &Algo;
+  Session *SP;
+
+public:
+  ARMBasicMCBuilder(ARMBasicMCBuilder &B)
+    : Opcode(B.Opcode), Format(B.Format), NumOps(B.NumOps), Algo(B.Algo),
+      SP(B.SP)
+  {}
+
+  /// Opcode, Format, NumOperands, and Algo make an ARM Basic MCBuilder.
+  ARMBasicMCBuilder(unsigned opc, ARMFormat format, unsigned short num,
+                    const ARMAlgorithm &algo)
+    : Opcode(opc), Format(format), NumOps(num), Algo(algo), SP(0)
+  {}
+
+  void setSession(Session *sp) {
+    SP = sp;
+  }
+
+  /// TryPredicateAndSBitModifier - TryPredicateAndSBitModifier tries to process
+  /// the possible Predicate and SBitModifier, to build the remaining MCOperand
+  /// constituents.
+  bool TryPredicateAndSBitModifier(MCInst& MI, unsigned Opcode,
+      uint32_t insn, unsigned short NumOpsRemaning);
+
+  /// InITBlock - InITBlock returns true if we are inside an IT block.
+  bool InITBlock() {
+    if (SP)
+      return SP->ITCounter > 0;
+
+    return false;
+  }
+
+  /// Build - Build delegates to BuildIt to perform the heavy liftling.  After
+  /// that, it invokes RunBuildAfterHook where some housekeepings can be done.
+  virtual bool Build(MCInst &MI, uint32_t insn) {
+    bool Status = BuildIt(MI, insn);
+    return RunBuildAfterHook(Status, MI, insn);
+  }
+
+  /// BuildIt - BuildIt performs the build step for this ARM Basic MC Builder.
+  /// The general idea is to set the Opcode for the MCInst, followed by adding
+  /// the appropriate MCOperands to the MCInst.  ARM Basic MC Builder delegates
+  /// to the Algo (ARM Disassemble Algorithm) object to perform Format-specific
+  /// disassembly, followed by class method TryPredicateAndSBitModifier() to do
+  /// PredicateOperand and OptionalDefOperand which follow the Dst/Src Operands.
+  virtual bool BuildIt(MCInst &MI, uint32_t insn);
+
+  /// RunBuildAfterHook - RunBuildAfterHook performs operations deemed necessary
+  /// after BuildIt is finished.
+  virtual bool RunBuildAfterHook(bool Status, MCInst &MI, uint32_t insn);
+
+private:
+  /// Get condition of the current IT instruction.
+  unsigned GetITCond() {
+    assert(SP);
+    return slice(SP->ITState, 7, 4);
+  }
+};
+
+/// CreateMCBuilder - Return an ARMBasicMCBuilder that can build up the MC
+/// infrastructure of an MCInst given the Opcode and Format of the instr.
+/// Return NULL if it fails to create/return a proper builder.  API clients
+/// are responsible for freeing up of the allocated memory.  Cacheing can be
+/// performed by the API clients to improve performance.
+extern ARMBasicMCBuilder *CreateMCBuilder(unsigned Opcode, ARMFormat Format);
+
+} // namespace llvm
+
+#endif

Added: llvm/trunk/lib/Target/ARM/Disassembler/Makefile
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/Makefile?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/Makefile (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/Makefile Fri Apr  2 17:27:38 2010
@@ -0,0 +1,16 @@
+##===- lib/Target/ARM/Disassembler/Makefile ----------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../../..
+LIBRARYNAME = LLVMARMDisassembler
+
+# Hack: we need to include 'main' arm target directory to grab private headers
+CPPFLAGS = -I$(PROJ_OBJ_DIR)/.. -I$(PROJ_SRC_DIR)/..
+
+include $(LEVEL)/Makefile.common

Added: llvm/trunk/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h?rev=100233&view=auto
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h (added)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ThumbDisassemblerCore.h Fri Apr  2 17:27:38 2010
@@ -0,0 +1,2187 @@
+//===- ThumbDisassemblerCore.h - Thumb disassembler helpers -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains code for disassembling a Thumb instr.  It is to be included by
+// ARMDisassemblerCore.cpp because it contains the static DisassembleThumbFrm()
+// function which acts as the dispatcher to disassemble a Thumb instruction.
+//
+//===----------------------------------------------------------------------===//
+
+///////////////////////////////
+//                           //
+//     Utility Functions     //
+//                           //
+///////////////////////////////
+
+// Utilities for 16-bit Thumb instructions.
+/*
+15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0
+               [  tRt ]
+                      [ tRm ]  [ tRn ]  [ tRd ]
+                         D  [   Rm   ]  [  Rd ]
+
+                      [ imm3]
+               [    imm5    ]
+                   i     [    imm5   ]
+                            [       imm7      ]
+                         [       imm8         ]
+               [             imm11            ]
+
+            [   cond  ]
+*/
+
+// Extract tRt: Inst{10-8}.
+static inline unsigned getT1tRt(uint32_t insn) {
+  return slice(insn, 10, 8);
+}
+
+// Extract tRm: Inst{8-6}.
+static inline unsigned getT1tRm(uint32_t insn) {
+  return slice(insn, 8, 6);
+}
+
+// Extract tRn: Inst{5-3}.
+static inline unsigned getT1tRn(uint32_t insn) {
+  return slice(insn, 5, 3);
+}
+
+// Extract tRd: Inst{2-0}.
+static inline unsigned getT1tRd(uint32_t insn) {
+  return slice(insn, 2, 0);
+}
+
+// Extract [D:Rd]: Inst{7:2-0}.
+static inline unsigned getT1Rd(uint32_t insn) {
+  return slice(insn, 7, 7) << 3 | slice(insn, 2, 0);
+}
+
+// Extract Rm: Inst{6-3}.
+static inline unsigned getT1Rm(uint32_t insn) {
+  return slice(insn, 6, 3);
+}
+
+// Extract imm3: Inst{8-6}.
+static inline unsigned getT1Imm3(uint32_t insn) {
+  return slice(insn, 8, 6);
+}
+
+// Extract imm5: Inst{10-6}.
+static inline unsigned getT1Imm5(uint32_t insn) {
+  return slice(insn, 10, 6);
+}
+
+// Extract i:imm5: Inst{9:7-3}.
+static inline unsigned getT1Imm6(uint32_t insn) {
+  return slice(insn, 9, 9) << 5 | slice(insn, 7, 3);
+}
+
+// Extract imm7: Inst{6-0}.
+static inline unsigned getT1Imm7(uint32_t insn) {
+  return slice(insn, 6, 0);
+}
+
+// Extract imm8: Inst{7-0}.
+static inline unsigned getT1Imm8(uint32_t insn) {
+  return slice(insn, 7, 0);
+}
+
+// Extract imm11: Inst{10-0}.
+static inline unsigned getT1Imm11(uint32_t insn) {
+  return slice(insn, 10, 0);
+}
+
+// Extract cond: Inst{11-8}.
+static inline unsigned getT1Cond(uint32_t insn) {
+  return slice(insn, 11, 8);
+}
+
+static inline bool IsGPR(unsigned RegClass) {
+  return RegClass == ARM::GPRRegClassID;
+}
+
+// Utilities for 32-bit Thumb instructions.
+
+// Extract imm4: Inst{19-16}.
+static inline unsigned getImm4(uint32_t insn) {
+  return slice(insn, 19, 16);
+}
+
+// Extract imm3: Inst{14-12}.
+static inline unsigned getImm3(uint32_t insn) {
+  return slice(insn, 14, 12);
+}
+
+// Extract imm8: Inst{7-0}.
+static inline unsigned getImm8(uint32_t insn) {
+  return slice(insn, 7, 0);
+}
+
+// A8.6.61 LDRB (immediate, Thumb) and friends
+// +/-: Inst{9}
+// imm8: Inst{7-0}
+static inline int decodeImm8(uint32_t insn) {
+  int Offset = getImm8(insn);
+  return slice(insn, 9, 9) ? Offset : -Offset;
+}
+
+// Extract imm12: Inst{11-0}.
+static inline unsigned getImm12(uint32_t insn) {
+  return slice(insn, 11, 0);
+}
+
+// A8.6.63 LDRB (literal) and friends
+// +/-: Inst{23}
+// imm12: Inst{11-0}
+static inline int decodeImm12(uint32_t insn) {
+  int Offset = getImm12(insn);
+  return slice(insn, 23, 23) ? Offset : -Offset;
+}
+
+// Extract imm2: Inst{7-6}.
+static inline unsigned getImm2(uint32_t insn) {
+  return slice(insn, 7, 6);
+}
+
+// For BFI, BFC, t2SBFX, and t2UBFX.
+// Extract lsb: Inst{14-12:7-6}.
+static inline unsigned getLsb(uint32_t insn) {
+  return getImm3(insn) << 2 | getImm2(insn);
+}
+
+// For BFI and BFC.
+// Extract msb: Inst{4-0}.
+static inline unsigned getMsb(uint32_t insn) {
+  return slice(insn, 4, 0);
+}
+
+// For t2SBFX and t2UBFX.
+// Extract widthminus1: Inst{4-0}.
+static inline unsigned getWidthMinus1(uint32_t insn) {
+  return slice(insn, 4, 0);
+}
+
+// For t2ADDri12 and t2SUBri12.
+// imm12 = i:imm3:imm8;
+static inline unsigned getIImm3Imm8(uint32_t insn) {
+  return slice(insn, 26, 26) << 11 | getImm3(insn) << 8 | getImm8(insn);
+}
+
+// For t2MOVi16 and t2MOVTi16.
+// imm16 = imm4:i:imm3:imm8;
+static inline unsigned getImm16(uint32_t insn) {
+  return getImm4(insn) << 12 | slice(insn, 26, 26) << 11 |
+    getImm3(insn) << 8 | getImm8(insn);
+}
+
+// Inst{5-4} encodes the shift type.
+static inline unsigned getShiftTypeBits(uint32_t insn) {
+  return slice(insn, 5, 4);
+}
+
+// Inst{14-12}:Inst{7-6} encodes the imm5 shift amount.
+static inline unsigned getShiftAmtBits(uint32_t insn) {
+  return getImm3(insn) << 2 | getImm2(insn);
+}
+
+// A8.6.17 BFC
+// Encoding T1 ARMv6T2, ARMv7
+// LLVM-specific encoding for #<lsb> and #<width>
+static inline uint32_t getBitfieldInvMask(uint32_t insn) {
+  uint32_t lsb = getImm3(insn) << 2 | getImm2(insn);
+  uint32_t msb = getMsb(insn);
+  uint32_t Val = 0;
+  assert(lsb <= msb && "Encoding error: lsb > msb");
+  for (uint32_t i = lsb; i <= msb; ++i)
+    Val |= (1 << i);
+  return ~Val;
+}
+
+// A8.4 Shifts applied to a register
+// A8.4.1 Constant shifts
+// A8.4.3 Pseudocode details of instruction-specified shifts and rotates
+//
+// decodeImmShift() returns the shift amount and the the shift opcode.
+// Note that, as of Jan-06-2010, LLVM does not support rrx shifted operands yet.
+static inline unsigned decodeImmShift(unsigned bits2, unsigned imm5,
+                                      ARM_AM::ShiftOpc &ShOp) {
+
+  assert(imm5 < 32 && "Invalid imm5 argument");
+  switch (bits2) {
+  default: assert(0 && "No such value");
+  case 0:
+    ShOp = ARM_AM::lsl;
+    return imm5;
+  case 1:
+    ShOp = ARM_AM::lsr;
+    return (imm5 == 0 ? 32 : imm5);
+  case 2:
+    ShOp = ARM_AM::asr;
+    return (imm5 == 0 ? 32 : imm5);
+  case 3:
+    ShOp = (imm5 == 0 ? ARM_AM::rrx : ARM_AM::ror);
+    return (imm5 == 0 ? 1 : imm5);
+  }
+}
+
+// A6.3.2 Modified immediate constants in Thumb instructions
+//
+// ThumbExpandImm() returns the modified immediate constant given an imm12 for
+// Thumb data-processing instructions with modified immediate.
+// See also A6.3.1 Data-processing (modified immediate).
+static inline unsigned ThumbExpandImm(unsigned imm12) {
+  assert(imm12 <= 0xFFF && "Invalid imm12 argument");
+
+  // If the leading two bits is 0b00, the modified immediate constant is
+  // obtained by splatting the low 8 bits into the first byte, every other byte,
+  // or every byte of a 32-bit value.
+  //
+  // Otherwise, a rotate right of '1':imm12<6:0> by the amount imm12<11:7> is
+  // performed.
+
+  if (slice(imm12, 11, 10) == 0) {
+    unsigned short control = slice(imm12, 9, 8);
+    unsigned imm8 = slice(imm12, 7, 0);
+    switch (control) {
+    default:
+      assert(0 && "No such value");
+      return 0;
+    case 0:
+      return imm8;
+    case 1:
+      return imm8 << 16 | imm8;
+    case 2:
+      return imm8 << 24 | imm8 << 8;
+    case 3:
+      return imm8 << 24 | imm8 << 16 | imm8 << 8 | imm8;
+    }
+  } else {
+    // A rotate is required.
+    unsigned Val = 1 << 7 | slice(imm12, 6, 0);
+    unsigned Amt = slice(imm12, 11, 7);
+    return ARM_AM::rotr32(Val, Amt);
+  }
+}
+
+static inline int decodeImm32_B_EncodingT3(uint32_t insn) {
+  bool S = slice(insn, 26, 26);
+  bool J1 = slice(insn, 13, 13);
+  bool J2 = slice(insn, 11, 11);
+  unsigned Imm21 = slice(insn, 21, 16) << 12 | slice(insn, 10, 0) << 1;
+  if (S) Imm21 |= 1 << 20;
+  if (J2) Imm21 |= 1 << 19;
+  if (J1) Imm21 |= 1 << 18;
+
+  return SignExtend32<21>(Imm21);
+}
+
+static inline int decodeImm32_B_EncodingT4(uint32_t insn) {
+  unsigned S = slice(insn, 26, 26);
+  bool I1 = slice(insn, 13, 13) == S;
+  bool I2 = slice(insn, 11, 11) == S;
+  unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 0) << 1;
+  if (S) Imm25 |= 1 << 24;
+  if (I1) Imm25 |= 1 << 23;
+  if (I2) Imm25 |= 1 << 22;
+
+  return SignExtend32<25>(Imm25);
+}
+
+static inline int decodeImm32_BL(uint32_t insn) {
+  unsigned S = slice(insn, 26, 26);
+  bool I1 = slice(insn, 13, 13) == S;
+  bool I2 = slice(insn, 11, 11) == S;
+  unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 0) << 1;
+  if (S) Imm25 |= 1 << 24;
+  if (I1) Imm25 |= 1 << 23;
+  if (I2) Imm25 |= 1 << 22;
+
+  return SignExtend32<25>(Imm25);
+}
+
+static inline int decodeImm32_BLX(uint32_t insn) {
+  unsigned S = slice(insn, 26, 26);
+  bool I1 = slice(insn, 13, 13) == S;
+  bool I2 = slice(insn, 11, 11) == S;
+  unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 1) << 2;
+  if (S) Imm25 |= 1 << 24;
+  if (I1) Imm25 |= 1 << 23;
+  if (I2) Imm25 |= 1 << 22;
+
+  return SignExtend32<25>(Imm25);
+}
+
+// See, for example, A8.6.221 SXTAB16.
+static inline unsigned decodeRotate(uint32_t insn) {
+  unsigned rotate = slice(insn, 5, 4);
+  return rotate << 3;
+}
+
+///////////////////////////////////////////////
+//                                           //
+// Thumb1 instruction disassembly functions. //
+//                                           //
+///////////////////////////////////////////////
+
+// See "Utilities for 16-bit Thumb instructions" for register naming convention.
+
+// A6.2.1 Shift (immediate), add, subtract, move, and compare
+//
+// shift immediate:         tRd CPSR tRn imm5
+// add/sub register:        tRd CPSR tRn tRm
+// add/sub 3-bit immediate: tRd CPSR tRn imm3
+// add/sub 8-bit immediate: tRt CPSR tRt(TIED_TO) imm8
+// mov/cmp immediate:       tRt [CPSR] imm8 (CPSR present for mov)
+//
+// Special case:
+// tMOVSr:                  tRd tRn
+static bool DisassembleThumb1General(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO Builder) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID
+         && "Invalid arguments");
+
+  bool Imm3 = (Opcode == ARM::tADDi3 || Opcode == ARM::tSUBi3);
+
+  // Use Rt implies use imm8.
+  bool UseRt = (Opcode == ARM::tADDi8 || Opcode == ARM::tSUBi8 ||
+                Opcode == ARM::tMOVi8 || Opcode == ARM::tCMPi8);
+
+  // Add the destination operand.
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(ARM::tGPRRegClassID,
+                                  UseRt ? getT1tRt(insn) : getT1tRd(insn))));
+  ++OpIdx;
+
+  // Check whether the next operand to be added is a CCR Register.
+  if (OpInfo[OpIdx].RegClass == ARM::CCRRegClassID) {
+    assert(OpInfo[OpIdx].isOptionalDef() && "Optional def operand expected");
+    MI.addOperand(MCOperand::CreateReg(Builder->InITBlock() ? 0 : ARM::CPSR));
+    ++OpIdx;
+  }
+
+  // Check whether the next operand to be added is a Thumb1 Register.
+  assert(OpIdx < NumOps && "More operands expected");
+  if (OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
+    // For UseRt, the reg operand is tied to the first reg operand.
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::tGPRRegClassID,
+                                    UseRt ? getT1tRt(insn) : getT1tRn(insn))));
+    ++OpIdx;
+  }
+
+  // Special case for tMOVSr.
+  if (OpIdx == NumOps)
+    return true;
+
+  // The next available operand is either a reg operand or an imm operand.
+  if (OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
+    // Three register operand instructions.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                       getT1tRm(insn))));
+  } else {
+    assert(OpInfo[OpIdx].RegClass == 0 &&
+           !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()
+           && "Pure imm operand expected");
+    MI.addOperand(MCOperand::CreateImm(UseRt ? getT1Imm8(insn)
+                                             : (Imm3 ? getT1Imm3(insn)
+                                                     : getT1Imm5(insn))));
+  }
+  ++OpIdx;
+
+  return true;
+}
+
+// A6.2.2 Data-processing
+//
+// tCMPr, tTST, tCMN: tRd tRn
+// tMVN, tRSB:        tRd CPSR tRn
+// Others:            tRd CPSR tRd(TIED_TO) tRn
+static bool DisassembleThumb1DP(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO Builder) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         (OpInfo[1].RegClass == ARM::CCRRegClassID
+          || OpInfo[1].RegClass == ARM::tGPRRegClassID)
+         && "Invalid arguments");
+
+  // Add the destination operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRd(insn))));
+  ++OpIdx;
+
+  // Check whether the next operand to be added is a CCR Register.
+  if (OpInfo[OpIdx].RegClass == ARM::CCRRegClassID) {
+    assert(OpInfo[OpIdx].isOptionalDef() && "Optional def operand expected");
+    MI.addOperand(MCOperand::CreateReg(Builder->InITBlock() ? 0 : ARM::CPSR));
+    ++OpIdx;
+  }
+
+  // We have either { tRd(TIED_TO), tRn } or { tRn } remaining.
+  // Process the TIED_TO operand first.
+
+  assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID
+         && "Thumb reg operand expected");
+  int Idx;
+  if ((Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+    // The reg operand is tied to the first reg operand.
+    MI.addOperand(MI.getOperand(Idx));
+    ++OpIdx;
+  }
+
+  // Process possible next reg operand.
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
+    // Add tRn operand.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                       getT1tRn(insn))));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// A6.2.3 Special data instructions and branch and exchange
+//
+// tADDhirr: Rd Rd(TIED_TO) Rm
+// tCMPhir:  Rd Rm
+// tMOVr, tMOVgpr2gpr, tMOVgpr2tgpr, tMOVtgpr2gpr: Rd|tRd Rm|tRn
+// tBX_RET: 0 operand
+// tBX_RET_vararg: Rm
+// tBLXr_r9: Rm
+static bool DisassembleThumb1Special(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  // tBX_RET has 0 operand.
+  if (NumOps == 0)
+    return true;
+
+  // BX/BLX has 1 reg operand: Rm.
+  if (NumOps == 1) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       getT1Rm(insn))));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  // Add the destination operand.
+  unsigned RegClass = OpInfo[OpIdx].RegClass;
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass,
+                                  IsGPR(RegClass) ? getT1Rd(insn)
+                                                  : getT1tRd(insn))));
+  ++OpIdx;
+
+  // We have either { Rd(TIED_TO), Rm } or { Rm|tRn } remaining.
+  // Process the TIED_TO operand first.
+
+  assert(OpIdx < NumOps && "More operands expected");
+  int Idx;
+  if ((Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+    // The reg operand is tied to the first reg operand.
+    MI.addOperand(MI.getOperand(Idx));
+    ++OpIdx;
+  }
+
+  // The next reg operand is either Rm or tRn.
+  assert(OpIdx < NumOps && "More operands expected");
+  RegClass = OpInfo[OpIdx].RegClass;
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(RegClass,
+                                  IsGPR(RegClass) ? getT1Rm(insn)
+                                                  : getT1tRn(insn))));
+  ++OpIdx;
+
+  return true;
+}
+
+// A8.6.59 LDR (literal)
+//
+// tLDRpci: tRt imm8*4
+static bool DisassembleThumb1LdPC(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         (OpInfo[1].RegClass == 0 &&
+          !OpInfo[1].isPredicate() &&
+          !OpInfo[1].isOptionalDef())
+         && "Invalid arguments");
+
+  // Add the destination operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRt(insn))));
+
+  // And the (imm8 << 2) operand.
+  MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn) << 2));
+
+  NumOpsAdded = 2;
+
+  return true;
+}
+
+// Thumb specific addressing modes (see ARMInstrThumb.td):
+//
+// t_addrmode_rr := reg + reg
+//
+// t_addrmode_s4 := reg + reg
+//                  reg + imm5 * 4
+//
+// t_addrmode_s2 := reg + reg
+//                  reg + imm5 * 2
+//
+// t_addrmode_s1 := reg + reg
+//                  reg + imm5
+//
+// t_addrmode_sp := sp + imm8 * 4
+//
+
+// A6.2.4 Load/store single data item
+//
+// Load/Store Register (reg|imm):      tRd tRn imm5 tRm
+// Load Register Signed Byte|Halfword: tRd tRn tRm
+static bool DisassembleThumb1LdSt(unsigned opA, MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  // Table A6-5 16-bit Thumb Load/store instructions
+  // opA = 0b0101 for STR/LDR (register) and friends.
+  // Otherwise, we have STR/LDR (immediate) and friends.
+  bool Imm5 = (opA != 5);
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::tGPRRegClassID
+         && OpInfo[1].RegClass == ARM::tGPRRegClassID
+         && "Expect >= 2 operands and first two as thumb reg operands");
+
+  // Add the destination reg and the base reg.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRd(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRn(insn))));
+  OpIdx = 2;
+
+  // We have either { imm5, tRm } or { tRm } remaining.
+  // Process the imm5 first.  Note that STR/LDR (register) should skip the imm5
+  // offset operand for t_addrmode_s[1|2|4].
+
+  assert(OpIdx < NumOps && "More operands expected");
+
+  if (OpInfo[OpIdx].RegClass == 0 && !OpInfo[OpIdx].isPredicate() &&
+      !OpInfo[OpIdx].isOptionalDef()) {
+
+    MI.addOperand(MCOperand::CreateImm(Imm5 ? getT1Imm5(insn) : 0));
+    ++OpIdx;
+  }
+
+  // The next reg operand is tRm, the offset.
+  assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID
+         && "Thumb reg operand expected");
+  MI.addOperand(MCOperand::CreateReg(Imm5 ? 0
+                                          : getRegisterEnum(ARM::tGPRRegClassID,
+                                                            getT1tRm(insn))));
+  ++OpIdx;
+
+  return true;
+}
+
+// A6.2.4 Load/store single data item
+//
+// Load/Store Register SP relative: tRt ARM::SP imm8
+static bool DisassembleThumb1LdStSP(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert((Opcode == ARM::tLDRspi || Opcode == ARM::tSTRspi)
+         && "Invalid opcode");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         (OpInfo[2].RegClass == 0 &&
+          !OpInfo[2].isPredicate() &&
+          !OpInfo[2].isOptionalDef())
+         && "Invalid arguments");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRt(insn))));
+  MI.addOperand(MCOperand::CreateReg(ARM::SP));
+  MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
+  NumOpsAdded = 3;
+  return true;
+}
+
+// Table A6-1 16-bit Thumb instruction encoding
+// A8.6.10 ADR
+//
+// tADDrPCi: tRt imm8
+static bool DisassembleThumb1AddPCi(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert(Opcode == ARM::tADDrPCi && "Invalid opcode");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         (OpInfo[1].RegClass == 0 &&
+          !OpInfo[1].isPredicate() &&
+          !OpInfo[1].isOptionalDef())
+         && "Invalid arguments");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRt(insn))));
+  MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
+  NumOpsAdded = 2;
+  return true;
+}
+
+// Table A6-1 16-bit Thumb instruction encoding
+// A8.6.8 ADD (SP plus immediate)
+//
+// tADDrSPi: tRt ARM::SP imm8
+static bool DisassembleThumb1AddSPi(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert(Opcode == ARM::tADDrSPi && "Invalid opcode");
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         (OpInfo[2].RegClass == 0 &&
+          !OpInfo[2].isPredicate() &&
+          !OpInfo[2].isOptionalDef())
+         && "Invalid arguments");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRt(insn))));
+  MI.addOperand(MCOperand::CreateReg(ARM::SP));
+  MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
+  NumOpsAdded = 3;
+  return true;
+}
+
+// tPUSH, tPOP: Pred-Imm Pred-CCR register_list
+//
+// where register_list = low registers + [lr] for PUSH or
+//                       low registers + [pc] for POP
+//
+// "low registers" is specified by Inst{7-0}
+// lr|pc is specified by Inst{8}
+static bool DisassembleThumb1PushPop(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert((Opcode == ARM::tPUSH || Opcode == ARM::tPOP) && "Invalid opcode");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  // Handling the two predicate operands before the reglist.
+  MI.addOperand(MCOperand::CreateImm(ARMCC::AL));
+  MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+  OpIdx = 2;
+
+  // Fill the variadic part of reglist.
+  unsigned RegListBits = slice(insn, 8, 8) << (Opcode == ARM::tPUSH ? 14 : 15)
+    | slice(insn, 7, 0);
+  for (unsigned i = 0; i < 16; ++i) {
+    if ((RegListBits >> i) & 1) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         i)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+// A6.2.5 Miscellaneous 16-bit instructions
+// Delegate to DisassembleThumb1PushPop() for tPUSH & tPOP.
+//
+// tADDspi, tSUBspi: ARM::SP ARM::SP(TIED_TO) imm7
+// t2IT:             firstcond=Inst{7-4} mask=Inst{3-0}
+// tCBNZ, tCBZ:      tRd imm6*2
+// tBKPT:            imm8
+// tNOP, tSEV, tYIELD, tWFE, tWFI:
+//   no operand (except predicate pair)
+// tSETENDBE, tSETENDLE, :
+//   no operand
+// Others:           tRd tRn
+static bool DisassembleThumb1Misc(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  if (NumOps == 0)
+    return true;
+
+  if (Opcode == ARM::tPUSH || Opcode == ARM::tPOP)
+    return DisassembleThumb1PushPop(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  // Predicate operands are handled elsewhere.
+  if (NumOps == 2 &&
+      OpInfo[0].isPredicate() && OpInfo[1].isPredicate() &&
+      OpInfo[0].RegClass == 0 && OpInfo[1].RegClass == ARM::CCRRegClassID) {
+    return true;
+  }
+
+  if (Opcode == ARM::tADDspi || Opcode == ARM::tSUBspi) {
+    // Special case handling for tADDspi and tSUBspi.
+    // A8.6.8 ADD (SP plus immediate) & A8.6.215 SUB (SP minus immediate)
+    MI.addOperand(MCOperand::CreateReg(ARM::SP));
+    MI.addOperand(MCOperand::CreateReg(ARM::SP));
+    MI.addOperand(MCOperand::CreateImm(getT1Imm7(insn)));
+    NumOpsAdded = 3;
+    return true;
+  }
+
+  if (Opcode == ARM::t2IT) {
+    // Special case handling for If-Then.
+    // A8.6.50 IT
+    // Tag the (firstcond[0] bit << 4) along with mask.
+
+    // firstcond
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 7, 4)));
+
+    // firstcond[0] and mask
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));
+    NumOpsAdded = 2;
+    return true;
+  }
+
+  if (Opcode == ARM::tBKPT) {
+    MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn))); // breakpoint value
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // CPS has a singleton $opt operand that contains the following information:
+  // opt{4-0} = don't care
+  // opt{5} = 0 (false)
+  // opt{8-6} = AIF from Inst{2-0}
+  // opt{10-9} = 1:imod from Inst{4} with 0b10 as enable and 0b11 as disable
+  if (Opcode == ARM::tCPS) {
+    unsigned Option = slice(insn, 2, 0) << 6 | slice(insn, 4, 4) << 9 | 1 << 10;
+    MI.addOperand(MCOperand::CreateImm(Option));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
+         (OpInfo[1].RegClass==0 || OpInfo[1].RegClass==ARM::tGPRRegClassID)
+         && "Expect >=2 operands");
+
+  // Add the destination operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                     getT1tRd(insn))));
+
+  if (OpInfo[1].RegClass == ARM::tGPRRegClassID) {
+    // Two register instructions.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                       getT1tRn(insn))));
+  } else {
+    // CBNZ, CBZ
+    assert((Opcode == ARM::tCBNZ || Opcode == ARM::tCBZ) && "Invalid opcode");
+    MI.addOperand(MCOperand::CreateImm(getT1Imm6(insn) * 2));
+  }
+
+  NumOpsAdded = 2;
+
+  return true;
+}
+
+// A8.6.53  LDM / LDMIA
+// A8.6.189 STM / STMIA
+//
+// tLDM_UPD/tSTM_UPD: tRt tRt AM4ModeImm Pred-Imm Pred-CCR register_list
+// tLDM:              tRt AM4ModeImm Pred-Imm Pred-CCR register_list
+static bool DisassembleThumb1LdStMul(bool Ld, MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert((Opcode == ARM::tLDM || Opcode == ARM::tLDM_UPD ||
+          Opcode == ARM::tSTM_UPD) && "Invalid opcode");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  unsigned tRt = getT1tRt(insn);
+  unsigned RegListBits = slice(insn, 7, 0);
+
+  OpIdx = 0;
+
+  // WB register, if necessary.
+  if (Opcode == ARM::tLDM_UPD || Opcode == ARM::tSTM_UPD) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       tRt)));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     tRt)));
+  ++OpIdx;
+
+  // A8.6.53 LDM / LDMIA / LDMFD - Encoding T1
+  MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM4ModeImm(ARM_AM::ia)));
+  ++OpIdx;
+
+  // Handling the two predicate operands before the reglist.
+  MI.addOperand(MCOperand::CreateImm(ARMCC::AL));
+  MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+  OpIdx += 2;
+
+  // Fill the variadic part of reglist.
+  for (unsigned i = 0; i < 8; ++i) {
+    if ((RegListBits >> i) & 1) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::tGPRRegClassID,
+                                                         i)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+static bool DisassembleThumb1LdMul(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+  return DisassembleThumb1LdStMul(true, MI, Opcode, insn, NumOps, NumOpsAdded);
+}
+
+static bool DisassembleThumb1StMul(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+  return DisassembleThumb1LdStMul(false, MI, Opcode, insn, NumOps, NumOpsAdded);
+}
+
+// A8.6.16 B Encoding T1
+// cond = Inst{11-8} & imm8 = Inst{7-0}
+// imm32 = SignExtend(imm8:'0', 32)
+//
+// tBcc: offset Pred-Imm Pred-CCR
+// tSVC: imm8 Pred-Imm Pred-CCR
+// tTRAP: 0 operand (early return)
+static bool DisassembleThumb1CondBr(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  if (Opcode == ARM::tTRAP)
+    return true;
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  assert(NumOps == 3 && OpInfo[0].RegClass == 0 &&
+         OpInfo[1].isPredicate() && OpInfo[2].RegClass == ARM::CCRRegClassID
+         && "Exactly 3 operands expected");
+
+  unsigned Imm8 = getT1Imm8(insn);
+  MI.addOperand(MCOperand::CreateImm(
+                  Opcode == ARM::tBcc ? SignExtend32<9>(Imm8 << 1) + 4
+                                      : (int)Imm8));
+
+  // Predicate operands by ARMBasicMCBuilder::TryPredicateAndSBitModifier().
+  NumOpsAdded = 1;
+
+  return true;
+}
+
+// A8.6.16 B Encoding T2
+// imm11 = Inst{10-0}
+// imm32 = SignExtend(imm11:'0', 32)
+//
+// tB: offset
+static bool DisassembleThumb1Br(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  assert(NumOps == 1 && OpInfo[0].RegClass == 0 && "1 imm operand expected");
+
+  unsigned Imm11 = getT1Imm11(insn);
+
+  // When executing a Thumb instruction, PC reads as the address of the current
+  // instruction plus 4.  The assembler subtracts 4 from the difference between
+  // the branch instruction and the target address, disassembler has to add 4 to
+  // to compensate.
+  MI.addOperand(MCOperand::CreateImm(SignExtend32<12>(Imm11 << 1) + 4));
+
+  NumOpsAdded = 1;
+
+  return true;
+
+}
+
+// See A6.2 16-bit Thumb instruction encoding for instruction classes
+// corresponding to op.
+//
+// Table A6-1 16-bit Thumb instruction encoding (abridged)
+// op		Instruction or instruction class
+// ------	--------------------------------------------------------------------
+// 00xxxx	Shift (immediate), add, subtract, move, and compare on page A6-7
+// 010000	Data-processing on page A6-8
+// 010001	Special data instructions and branch and exchange on page A6-9
+// 01001x	Load from Literal Pool, see LDR (literal) on page A8-122
+// 0101xx	Load/store single data item on page A6-10
+// 011xxx
+// 100xxx
+// 10100x	Generate PC-relative address, see ADR on page A8-32
+// 10101x	Generate SP-relative address, see ADD (SP plus immediate) on page A8-28
+// 1011xx	Miscellaneous 16-bit instructions on page A6-11
+// 11000x	Store multiple registers, see STM / STMIA / STMEA on page A8-374
+// 11001x	Load multiple registers, see LDM / LDMIA / LDMFD on page A8-110 a
+// 1101xx	Conditional branch, and Supervisor Call on page A6-13
+// 11100x	Unconditional Branch, see B on page A8-44
+//
+static bool DisassembleThumb1(uint16_t op,
+    MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO Builder) {
+
+  unsigned op1 = slice(op, 5, 4);
+  unsigned op2 = slice(op, 3, 2);
+  unsigned op3 = slice(op, 1, 0);
+  unsigned opA = slice(op, 5, 2);
+  switch (op1) {
+  case 0:
+    // A6.2.1 Shift (immediate), add, subtract, move, and compare
+    return DisassembleThumb1General(MI, Opcode, insn, NumOps, NumOpsAdded,
+                                    Builder);
+  case 1:
+    switch (op2) {
+    case 0:
+      switch (op3) {
+      case 0:
+        // A6.2.2 Data-processing
+        return DisassembleThumb1DP(MI, Opcode, insn, NumOps, NumOpsAdded,
+                                   Builder);
+      case 1:
+        // A6.2.3 Special data instructions and branch and exchange
+        return DisassembleThumb1Special(MI, Opcode, insn, NumOps, NumOpsAdded);
+      default:
+        // A8.6.59 LDR (literal)
+        return DisassembleThumb1LdPC(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+      break;
+    default:
+      // A6.2.4 Load/store single data item
+      return DisassembleThumb1LdSt(opA, MI, Opcode, insn, NumOps, NumOpsAdded);
+      break;
+    }
+    break;
+  case 2:
+    switch (op2) {
+    case 0:
+      // A6.2.4 Load/store single data item
+      return DisassembleThumb1LdSt(opA, MI, Opcode, insn, NumOps, NumOpsAdded);
+    case 1:
+      // A6.2.4 Load/store single data item
+      return DisassembleThumb1LdStSP(MI, Opcode, insn, NumOps, NumOpsAdded);
+    case 2:
+      if (op3 <= 1) {
+        // A8.6.10 ADR
+        return DisassembleThumb1AddPCi(MI, Opcode, insn, NumOps, NumOpsAdded);
+      } else {
+        // A8.6.8 ADD (SP plus immediate)
+        return DisassembleThumb1AddSPi(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+    default:
+      // A6.2.5 Miscellaneous 16-bit instructions
+      return DisassembleThumb1Misc(MI, Opcode, insn, NumOps, NumOpsAdded);
+    }
+    break;
+  case 3:
+    switch (op2) {
+    case 0:
+      if (op3 <= 1) {
+        // A8.6.189 STM / STMIA / STMEA
+        return DisassembleThumb1StMul(MI, Opcode, insn, NumOps, NumOpsAdded);
+      } else {
+        // A8.6.53 LDM / LDMIA / LDMFD
+        return DisassembleThumb1LdMul(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+    case 1:
+      // A6.2.6 Conditional branch, and Supervisor Call
+      return DisassembleThumb1CondBr(MI, Opcode, insn, NumOps, NumOpsAdded);
+    case 2:
+      // Unconditional Branch, see B on page A8-44
+      return DisassembleThumb1Br(MI, Opcode, insn, NumOps, NumOpsAdded);
+    default:
+      assert(0 && "Unreachable code");
+      break;
+    }
+    break;
+  default:
+    assert(0 && "Unreachable code");
+    break;
+  }
+
+  return false;
+}
+
+///////////////////////////////////////////////
+//                                           //
+// Thumb2 instruction disassembly functions. //
+//                                           //
+///////////////////////////////////////////////
+
+///////////////////////////////////////////////////////////
+//                                                       //
+// Note: the register naming follows the ARM convention! //
+//                                                       //
+///////////////////////////////////////////////////////////
+
+static inline bool Thumb2SRSOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::t2SRSDBW: case ARM::t2SRSDB:
+  case ARM::t2SRSIAW: case ARM::t2SRSIA:
+    return true;
+  }
+}
+
+static inline bool Thumb2RFEOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::t2RFEDBW: case ARM::t2RFEDB:
+  case ARM::t2RFEIAW: case ARM::t2RFEIA:
+    return true;
+  }
+}
+
+// t2SRS[IA|DB]W/t2SRS[IA|DB]: mode_imm = Inst{4-0}
+static bool DisassembleThumb2SRS(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+  MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));
+  NumOpsAdded = 1;
+  return true;
+}
+
+// t2RFE[IA|DB]W/t2RFE[IA|DB]: Rn
+static bool DisassembleThumb2RFE(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  NumOpsAdded = 1;
+  return true;
+}
+
+static bool DisassembleThumb2LdStMul(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  if (Thumb2SRSOpcode(Opcode))
+    return DisassembleThumb2SRS(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  if (Thumb2RFEOpcode(Opcode))
+    return DisassembleThumb2RFE(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  assert((Opcode == ARM::t2LDM || Opcode == ARM::t2LDM_UPD ||
+          Opcode == ARM::t2STM || Opcode == ARM::t2STM_UPD)
+         && "Invalid opcode");
+  assert(NumOps >= 5 && "Thumb2 LdStMul expects NumOps >= 5");
+
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  unsigned Base = getRegisterEnum(ARM::GPRRegClassID, decodeRn(insn));
+
+  // Writeback to base.
+  if (Opcode == ARM::t2LDM_UPD || Opcode == ARM::t2STM_UPD) {
+    MI.addOperand(MCOperand::CreateReg(Base));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(Base));
+  ++OpIdx;
+
+  ARM_AM::AMSubMode SubMode = getAMSubModeForBits(getPUBits(insn));
+  MI.addOperand(MCOperand::CreateImm(ARM_AM::getAM4ModeImm(SubMode)));
+  ++OpIdx;
+
+  // Handling the two predicate operands before the reglist.
+  MI.addOperand(MCOperand::CreateImm(ARMCC::AL));
+  MI.addOperand(MCOperand::CreateReg(ARM::CPSR));
+  OpIdx += 2;
+
+  // Fill the variadic part of reglist.
+  unsigned RegListBits = insn & ((1 << 16) - 1);
+  for (unsigned i = 0; i < 16; ++i) {
+    if ((RegListBits >> i) & 1) {
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         i)));
+      ++OpIdx;
+    }
+  }
+
+  return true;
+}
+
+// t2LDREX: Rd Rn
+// t2LDREXD: Rd Rs Rn
+// t2LDREXB, t2LDREXH: Rd Rn
+// t2STREX: Rs Rd Rn
+// t2STREXD: Rm Rd Rs Rn
+// t2STREXB, t2STREXH: Rm Rd Rn
+static bool DisassembleThumb2LdStEx(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && "Expect >=2 operands and first two as reg operands");
+
+  bool isStore = (ARM::t2STREX <= Opcode && Opcode <= ARM::t2STREXH);
+  bool isSW = (Opcode == ARM::t2LDREX || Opcode == ARM::t2STREX);
+  bool isDW = (Opcode == ARM::t2LDREXD || Opcode == ARM::t2STREXD);
+
+  // Add the destination operand for store.
+  if (isStore) {
+    MI.addOperand(MCOperand::CreateReg(
+                    getRegisterEnum(ARM::GPRRegClassID,
+                                    isSW ? decodeRs(insn) : decodeRm(insn))));
+    ++OpIdx;
+  }
+
+  // Source operand for store and destination operand for load.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  ++OpIdx;
+
+  // Thumb2 doubleword complication: with an extra source/destination operand.
+  if (isDW) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRs(insn))));
+    ++OpIdx;
+  }
+
+  // Finally add the pointer operand.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  ++OpIdx;
+
+  return true;
+}
+
+// LLVM, as of Jan-05-2010, does not output <Rt2>, i.e., Rs, in the asm.
+// Whereas the ARM Arch. Manual does not require that t2 = t+1 like in ARM ISA.
+//
+// t2LDRDi8: Rd Rs Rn imm8s4 (offset mode)
+// t2LDRDpci: Rd Rs imm8s4 (Not decoded, prefer the generic t2LDRDi8 version)
+// t2STRDi8: Rd Rs Rn imm8s4 (offset mode)
+//
+// Ditto for t2LDRD_PRE, t2LDRD_POST, t2STRD_PRE, t2STRD_POST, which are for
+// disassembly only and do not have a tied_to writeback base register operand.
+static bool DisassembleThumb2LdStDual(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 4
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && OpInfo[2].RegClass == ARM::GPRRegClassID
+         && OpInfo[3].RegClass == 0
+         && "Expect >= 4 operands and first 3 as reg operands");
+
+  // Add the <Rt> <Rt2> operands.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+
+  // Finally add (+/-)imm8*4, depending on the U bit.
+  int Offset = getImm8(insn) * 4;
+  if (getUBit(insn) == 0)
+    Offset = -Offset;
+  MI.addOperand(MCOperand::CreateImm(Offset));
+  NumOpsAdded = 4;
+
+  return true;
+}
+
+// PC-based defined for Codegen, which do not get decoded by design:
+//
+// t2TBB, t2TBH: Rm immDontCare immDontCare
+//
+// Generic version defined for disassembly:
+//
+// t2TBBgen, t2TBHgen: Rn Rm Pred-Imm Pred-CCR
+static bool DisassembleThumb2TB(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  assert(NumOps >= 2 && "Expect >= 2 operands");
+
+  // The generic version of TBB/TBH needs a base register.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  // Add the index register.
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  NumOpsAdded = 2;
+
+  return true;
+}
+
+static inline bool Thumb2ShiftOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::t2MOVCClsl: case ARM::t2MOVCClsr:
+  case ARM::t2MOVCCasr: case ARM::t2MOVCCror:
+  case ARM::t2LSLri:    case ARM::t2LSRri:
+  case ARM::t2ASRri:    case ARM::t2RORri:
+    return true;
+  }
+}
+
+// A6.3.11 Data-processing (shifted register)
+//
+// Two register operands (Rn=0b1111 no 1st operand reg): Rs Rm
+// Two register operands (Rs=0b1111 no dst operand reg): Rn Rm
+// Three register operands: Rs Rn Rm
+// Three register operands: (Rn=0b1111 Conditional Move) Rs Ro(TIED_TO) Rm
+//
+// Constant shifts t2_so_reg is a 2-operand unit corresponding to the Thumb2
+// register with shift forms: (Rm, ConstantShiftSpecifier).
+// Constant shift specifier: Imm = (ShOp | ShAmt<<3).
+//
+// There are special instructions, like t2MOVsra_flag and t2MOVsrl_flag, which
+// only require two register operands: Rd, Rm in ARM Reference Manual terms, and
+// nothing else, because the shift amount is already specified.
+// Similar case holds for t2MOVrx, t2ADDrr, ..., etc.
+static bool DisassembleThumb2DPSoReg(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  // Special case handling.
+  if (Opcode == ARM::t2BR_JT) {
+    assert(NumOps == 4
+           && OpInfo[0].RegClass == ARM::GPRRegClassID
+           && OpInfo[1].RegClass == ARM::GPRRegClassID
+           && OpInfo[2].RegClass == 0
+           && OpInfo[3].RegClass == 0
+           && "Exactlt 4 operands expect and first two as reg operands");
+    // Only need to populate the src reg operand.
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+    MI.addOperand(MCOperand::CreateReg(0));
+    MI.addOperand(MCOperand::CreateImm(0));
+    MI.addOperand(MCOperand::CreateImm(0));
+    NumOpsAdded = 4;
+    return true;
+  }
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2
+         && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && OpInfo[1].RegClass == ARM::GPRRegClassID
+         && "Expect >= 2 operands and first two as reg operands");
+
+  bool ThreeReg = (NumOps > 2 && OpInfo[2].RegClass == ARM::GPRRegClassID);
+  bool NoDstReg = (decodeRs(insn) == 0xF);
+
+  // Build the register operands, followed by the constant shift specifier.
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(ARM::GPRRegClassID,
+                                  NoDstReg ? decodeRn(insn) : decodeRs(insn))));
+  ++OpIdx;
+
+  if (ThreeReg) {
+    int Idx;
+    if ((Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+      // Process tied_to operand constraint.
+      MI.addOperand(MI.getOperand(Idx));
+    } else {
+      assert(!NoDstReg && "Internal error");
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         decodeRn(insn))));
+    }
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  ++OpIdx;
+
+  if (NumOps == OpIdx)
+    return true;
+
+  if (OpInfo[OpIdx].RegClass == 0 && !OpInfo[OpIdx].isPredicate()
+      && !OpInfo[OpIdx].isOptionalDef()) {
+
+    if (Thumb2ShiftOpcode(Opcode))
+      MI.addOperand(MCOperand::CreateImm(getShiftAmtBits(insn)));
+    else {
+      // Build the constant shift specifier operand.
+      unsigned bits2 = getShiftTypeBits(insn);
+      unsigned imm5 = getShiftAmtBits(insn);
+      ARM_AM::ShiftOpc ShOp = ARM_AM::no_shift;
+      unsigned ShAmt = decodeImmShift(bits2, imm5, ShOp);
+
+      // PKHBT/PKHTB are special in that we need the decodeImmShift() call to
+      // decode the shift amount from raw imm5 and bits2, but we DO NOT need
+      // to encode the ShOp, as it's in the asm string already.
+      if (Opcode == ARM::t2PKHBT || Opcode == ARM::t2PKHTB)
+        MI.addOperand(MCOperand::CreateImm(ShAmt));
+      else
+        MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, ShAmt)));
+    }
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// A6.3.1 Data-processing (modified immediate)
+//
+// Two register operands: Rs Rn ModImm
+// One register operands (Rs=0b1111 no explicit dest reg): Rn ModImm
+// One register operands (Rn=0b1111 no explicit src reg): Rs ModImm - {t2MOVi, t2MVNi}
+//
+// ModImm = ThumbExpandImm(i:imm3:imm8)
+static bool DisassembleThumb2DPModImm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && "Expect >= 2 operands and first one as reg operand");
+
+  bool TwoReg = (OpInfo[1].RegClass == ARM::GPRRegClassID);
+  bool NoDstReg = (decodeRs(insn) == 0xF);
+
+  // Build the register operands, followed by the modified immediate.
+
+  MI.addOperand(MCOperand::CreateReg(
+                  getRegisterEnum(ARM::GPRRegClassID,
+                                  NoDstReg ? decodeRn(insn) : decodeRs(insn))));
+  ++OpIdx;
+
+  if (TwoReg) {
+    assert(!NoDstReg && "Internal error");
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  // The modified immediate operand should come next.
+  assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0 &&
+         !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()
+         && "Pure imm operand expected");
+
+  // i:imm3:imm8
+  // A6.3.2 Modified immediate constants in Thumb instructions
+  unsigned imm12 = getIImm3Imm8(insn);
+  MI.addOperand(MCOperand::CreateImm(ThumbExpandImm(imm12)));
+  ++OpIdx;
+
+  return true;
+}
+
+static inline bool Thumb2SaturateOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  case ARM::t2SSATlsl: case ARM::t2SSATasr: case ARM::t2SSAT16:
+  case ARM::t2USATlsl: case ARM::t2USATasr: case ARM::t2USAT16:
+    return true;
+  default:
+    return false;
+  }
+}
+
+static inline unsigned decodeThumb2SaturatePos(unsigned Opcode, uint32_t insn) {
+  switch (Opcode) {
+  case ARM::t2SSATlsl:
+  case ARM::t2SSATasr:
+    return slice(insn, 4, 0) + 1;
+  case ARM::t2SSAT16:
+    return slice(insn, 3, 0) + 1;
+  case ARM::t2USATlsl:
+  case ARM::t2USATasr:
+    return slice(insn, 4, 0);
+  case ARM::t2USAT16:
+    return slice(insn, 3, 0);
+  default:
+    assert(0 && "Invalid opcode passed in");
+    return 0;
+  }
+}
+
+// A6.3.3 Data-processing (plain binary immediate)
+//
+// o t2ADDri12, t2SUBri12: Rs Rn imm12
+// o t2LEApcrel (ADR): Rs imm12
+// o t2BFC (BFC): Rs Ro(TIED_TO) bf_inv_mask_imm
+// o t2BFI (BFI) (Currently not defined in LLVM as of Jan-07-2010)
+// o t2MOVi16: Rs imm16
+// o t2MOVTi16: Rs imm16
+// o t2SBFX (SBFX): Rs Rn lsb width
+// o t2UBFX (UBFX): Rs Rn lsb width
+// o t2BFI (BFI): Rs Rn lsb width
+//
+// [Signed|Unsigned] Saturate [16]
+//
+// o t2SSAT[lsl|asr], t2USAT[lsl|asr]: Rs sat_pos Rn shamt
+// o t2SSAT16, t2USAT16: Rs sat_pos Rn
+static bool DisassembleThumb2DPBinImm(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::GPRRegClassID
+         && "Expect >= 2 operands and first one as reg operand");
+
+  bool TwoReg = (OpInfo[1].RegClass == ARM::GPRRegClassID);
+
+  // Build the register operand(s), followed by the immediate(s).
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+  ++OpIdx;
+
+  // t2SSAT/t2SSAT16/t2USAT/t2USAT16 has imm operand after Rd.
+  if (Thumb2SaturateOpcode(Opcode)) {
+    MI.addOperand(MCOperand::CreateImm(decodeThumb2SaturatePos(Opcode, insn)));
+
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+
+    if (Opcode == ARM::t2SSAT16 || Opcode == ARM::t2USAT16) {
+      OpIdx += 2;
+      return true;
+    }
+
+    // For SSAT operand reg (Rn) has been disassembled above.
+    // Now disassemble the shift amount.
+
+    // Inst{14-12:7-6} encodes the imm5 shift amount.
+    unsigned ShAmt = slice(insn, 14, 12) << 2 | slice(insn, 7, 6);
+
+    MI.addOperand(MCOperand::CreateImm(ShAmt));
+
+    OpIdx += 3;
+    return true;
+  }
+
+  if (TwoReg) {
+    assert(NumOps >= 3 && "Expect >= 3 operands");
+    int Idx;
+    if ((Idx = TID.getOperandConstraint(OpIdx, TOI::TIED_TO)) != -1) {
+      // Process tied_to operand constraint.
+      MI.addOperand(MI.getOperand(Idx));
+    } else {
+      // Add src reg operand.
+      MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                         decodeRn(insn))));
+    }
+    ++OpIdx;
+  }
+
+  assert(OpInfo[OpIdx].RegClass == 0 && !OpInfo[OpIdx].isPredicate()
+         && !OpInfo[OpIdx].isOptionalDef()
+         && "Pure imm operand expected");
+
+  // Pre-increment OpIdx.
+  ++OpIdx;
+
+  if (Opcode == ARM::t2ADDri12 || Opcode == ARM::t2SUBri12
+      || Opcode == ARM::t2LEApcrel)
+    MI.addOperand(MCOperand::CreateImm(getIImm3Imm8(insn)));
+  else if (Opcode == ARM::t2MOVi16 || Opcode == ARM::t2MOVTi16)
+    MI.addOperand(MCOperand::CreateImm(getImm16(insn)));
+  else if (Opcode == ARM::t2BFC)
+    MI.addOperand(MCOperand::CreateImm(getBitfieldInvMask(insn)));
+  else {
+    // Handle the case of: lsb width
+    assert((Opcode == ARM::t2SBFX || Opcode == ARM::t2UBFX ||
+            Opcode == ARM::t2BFI) && "Invalid opcode");
+    MI.addOperand(MCOperand::CreateImm(getLsb(insn)));
+    if (Opcode == ARM::t2BFI) {
+      assert(getMsb(insn) >= getLsb(insn) && "Encoding error");
+      MI.addOperand(MCOperand::CreateImm(getMsb(insn) - getLsb(insn) + 1));
+    } else
+      MI.addOperand(MCOperand::CreateImm(getWidthMinus1(insn) + 1));
+
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// A6.3.4 Table A6-15 Miscellaneous control instructions
+// A8.6.41 DMB
+// A8.6.42 DSB
+// A8.6.49 ISB
+static inline bool t2MiscCtrlInstr(uint32_t insn) {
+  if (slice(insn, 31, 20) == 0xf3b && slice(insn, 15, 14) == 2 &&
+      slice(insn, 12, 12) == 0)
+    return true;
+
+  return false;
+}
+
+// A6.3.4 Branches and miscellaneous control
+//
+// A8.6.16 B
+// Branches: t2B, t2Bcc -> imm operand
+//
+// Branches: t2TPsoft -> no operand
+//
+// A8.6.23 BL, BLX (immediate)
+// Branches (defined in ARMInstrThumb.td): tBLr9, tBLXi_r9 -> imm operand
+//
+// A8.6.26
+// t2BXJ -> Rn
+//
+// Miscellaneous control: t2Int_MemBarrierV7 (and its t2DMB variants),
+// t2Int_SyncBarrierV7 (and its t2DSB varianst), t2ISBsy, t2CLREX
+//   -> no operand (except pred-imm pred-ccr for CLREX, memory barrier variants)
+//
+// Hint: t2NOP, t2YIELD, t2WFE, t2WFI, t2SEV
+//   -> no operand (except pred-imm pred-ccr)
+//
+// t2DBG -> imm4 = Inst{3-0}
+//
+// t2MRS/t2MRSsys -> Rs
+// t2MSR/t2MSRsys -> Rn mask=Inst{11-8}
+// t2SMC -> imm4 = Inst{19-16}
+static bool DisassembleThumb2BrMiscCtrl(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  if (NumOps == 0)
+    return true;
+
+  if (t2MiscCtrlInstr(insn))
+    return true;
+
+  switch (Opcode) {
+  case ARM::t2CLREX:
+  case ARM::t2NOP:
+  case ARM::t2YIELD:
+  case ARM::t2WFE:
+  case ARM::t2WFI:
+  case ARM::t2SEV:
+    return true;
+  default:
+    break;
+  }
+
+  // CPS has a singleton $opt operand that contains the following information:
+  // opt{4-0} = mode from Inst{4-0}
+  // opt{5} = changemode from Inst{8}
+  // opt{8-6} = AIF from Inst{7-5}
+  // opt{10-9} = imod from Inst{10-9} with 0b10 as enable and 0b11 as disable
+  if (Opcode == ARM::t2CPS) {
+    unsigned Option = slice(insn, 4, 0) | slice(insn, 8, 8) << 5 |
+      slice(insn, 7, 5) << 6 | slice(insn, 10, 9) << 9;
+    MI.addOperand(MCOperand::CreateImm(Option));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // DBG has its option specified in Inst{3-0}.
+  if (Opcode == ARM::t2DBG) {
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 3, 0)));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // MRS and MRSsys take one GPR reg Rs.
+  if (Opcode == ARM::t2MRS || Opcode == ARM::t2MRSsys) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRs(insn))));
+    NumOpsAdded = 1;
+    return true;
+  }
+  // BXJ takes one GPR reg Rn.
+  if (Opcode == ARM::t2BXJ) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    NumOpsAdded = 1;
+    return true;
+  }
+  // MSR and MSRsys take one GPR reg Rn, followed by the mask.
+  if (Opcode == ARM::t2MSR || Opcode == ARM::t2MSRsys || Opcode == ARM::t2BXJ) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 11, 8)));
+    NumOpsAdded = 2;
+    return true;
+  }
+  // SMC take imm4.
+  if (Opcode == ARM::t2SMC) {
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 16)));
+    NumOpsAdded = 1;
+    return true;
+  }
+
+  // Add the imm operand.
+  int Offset = 0;
+
+  switch (Opcode) {
+  default:
+    assert(0 && "Unreachable code");
+    return false;
+  case ARM::t2B:
+    Offset = decodeImm32_B_EncodingT4(insn);
+    break;
+  case ARM::t2Bcc:
+    Offset = decodeImm32_B_EncodingT3(insn);
+    break;
+  case ARM::tBLr9:
+    Offset = decodeImm32_BL(insn);
+    break;
+  case ARM::tBLXi_r9:
+    Offset = decodeImm32_BLX(insn);
+    break;
+  }
+  // When executing a Thumb instruction, PC reads as the address of the current
+  // instruction plus 4.  The assembler subtracts 4 from the difference between
+  // the branch instruction and the target address, disassembler has to add 4 to
+  // to compensate.
+  MI.addOperand(MCOperand::CreateImm(Offset + 4));
+
+  NumOpsAdded = 1;
+
+  return true;
+}
+
+static inline bool Thumb2PreloadOpcode(unsigned Opcode) {
+  switch (Opcode) {
+  default:
+    return false;
+  case ARM::t2PLDi12:   case ARM::t2PLDi8:   case ARM::t2PLDpci:
+  case ARM::t2PLDr:     case ARM::t2PLDs:
+  case ARM::t2PLDWi12:  case ARM::t2PLDWi8:  case ARM::t2PLDWpci:
+  case ARM::t2PLDWr:    case ARM::t2PLDWs:
+  case ARM::t2PLIi12:   case ARM::t2PLIi8:   case ARM::t2PLIpci:
+  case ARM::t2PLIr:     case ARM::t2PLIs:
+    return true;
+  }
+}
+
+static bool DisassembleThumb2PreLoad(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  // Preload Data/Instruction requires either 2 or 3 operands.
+  // t2PLDi12, t2PLDi8, t2PLDpci: Rn [+/-]imm12/imm8
+  // t2PLDr:                      Rn Rm
+  // t2PLDs:                      Rn Rm imm2=Inst{5-4}
+  // Same pattern applies for t2PLDW* and t2PLI*.
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 2 operands and first one as reg operand");
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+  ++OpIdx;
+
+  if (OpInfo[OpIdx].RegClass == ARM::GPRRegClassID) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRm(insn))));
+  } else {
+    assert(OpInfo[OpIdx].RegClass == 0 && !OpInfo[OpIdx].isPredicate()
+           && !OpInfo[OpIdx].isOptionalDef()
+           && "Pure imm operand expected");
+    int Offset = 0;
+    if (Opcode == ARM::t2PLDpci || Opcode == ARM::t2PLDWpci ||
+             Opcode == ARM::t2PLIpci) {
+      bool Negative = slice(insn, 23, 23) == 0;
+      unsigned Imm12 = getImm12(insn);
+      Offset = Negative ? -1 - Imm12 : 1 * Imm12;      
+    } else if (Opcode == ARM::t2PLDi8 || Opcode == ARM::t2PLDWi8 ||
+               Opcode == ARM::t2PLIi8) {
+      // A8.6.117 Encoding T2: add = FALSE
+      unsigned Imm8 = getImm8(insn);
+      Offset = -1 - Imm8;
+    } else // The i12 forms.  See, for example, A8.6.117 Encoding T1.
+      Offset = decodeImm12(insn);
+    MI.addOperand(MCOperand::CreateImm(Offset));
+  }
+  ++OpIdx;
+
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0 &&
+      !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // Fills in the shift amount for t2PLDs, t2PLDWs, t2PLIs.
+    MI.addOperand(MCOperand::CreateImm(slice(insn, 5, 4)));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// A8.6.63 LDRB (literal)
+// A8.6.79 LDRSB (literal)
+// A8.6.75 LDRH (literal)
+// A8.6.83 LDRSH (literal)
+// A8.6.59 LDR (literal)
+//
+// These instrs calculate an address from the PC value and an immediate offset.
+// Rd Rn=PC (+/-)imm12 (+ if Inst{23} == 0b1)
+static bool DisassembleThumb2Ldpci(MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 2 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == 0 &&
+         "Expect >= 2 operands, first as reg, and second as imm operand");
+
+  // Build the register operand, followed by the (+/-)imm12 immediate.
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRd(insn))));
+
+  MI.addOperand(MCOperand::CreateImm(decodeImm12(insn)));
+
+  NumOpsAdded = 2;
+
+  return true;
+}
+
+// A6.3.10 Store single data item
+// A6.3.9 Load byte, memory hints
+// A6.3.8 Load halfword, memory hints
+// A6.3.7 Load word
+//
+// For example,
+//
+// t2LDRi12:   Rd Rn (+)imm12
+// t2LDRi8:    Rd Rn (+/-)imm8 (+ if Inst{9} == 0b1)
+// t2LDRs:     Rd Rn Rm ConstantShiftSpecifier (see also DisassembleThumb2DPSoReg)
+// t2LDR_POST: Rd Rn Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
+// t2LDR_PRE:  Rd Rn Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
+//
+// t2STRi12:   Rd Rn (+)imm12
+// t2STRi8:    Rd Rn (+/-)imm8 (+ if Inst{9} == 0b1)
+// t2STRs:     Rd Rn Rm ConstantShiftSpecifier (see also DisassembleThumb2DPSoReg)
+// t2STR_POST: Rn Rd Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
+// t2STR_PRE:  Rn Rd Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
+//
+// Note that for indexed modes, the Rn(TIED_TO) operand needs to be populated
+// correctly, as LLVM AsmPrinter depends on it.  For indexed stores, the first
+// operand is Rn; for all the other instructions, Rd is the first operand.
+//
+// Delegates to DisassembleThumb2PreLoad() for preload data/instruction.
+// Delegates to DisassembleThumb2Ldpci() for load * literal operations.
+static bool DisassembleThumb2LdSt(bool Load, MCInst &MI, unsigned Opcode,
+    uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  unsigned Rn = decodeRn(insn);
+
+  if (Thumb2PreloadOpcode(Opcode))
+    return DisassembleThumb2PreLoad(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  // See, for example, A6.3.7 Load word: Table A6-18 Load word.
+  if (Load && Rn == 15)
+    return DisassembleThumb2Ldpci(MI, Opcode, insn, NumOps, NumOpsAdded);
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 3 operands and first two as reg operands");
+
+  bool ThreeReg = (OpInfo[2].RegClass == ARM::GPRRegClassID);
+  bool TIED_TO = ThreeReg && TID.getOperandConstraint(2, TOI::TIED_TO) != -1;
+  bool Imm12 = !ThreeReg && slice(insn, 23, 23) == 1; // ARMInstrThumb2.td
+
+  // Build the register operands, followed by the immediate.
+  unsigned R0, R1, R2 = 0;
+  unsigned Rd = decodeRd(insn);
+  int Imm = 0;
+
+  if (!Load && TIED_TO) {
+    R0 = Rn;
+    R1 = Rd;
+  } else {
+    R0 = Rd;
+    R1 = Rn;
+  }
+  if (ThreeReg) {
+    if (TIED_TO) {
+      R2 = Rn;
+      Imm = decodeImm8(insn);
+    } else {
+      R2 = decodeRm(insn);
+      // See, for example, A8.6.64 LDRB (register).
+      // And ARMAsmPrinter::printT2AddrModeSoRegOperand().
+      // LSL is the default shift opc, and LLVM does not expect it to be encoded
+      // as part of the immediate operand.
+      // Imm = ARM_AM::getSORegOpc(ARM_AM::lsl, slice(insn, 5, 4));
+      Imm = slice(insn, 5, 4);
+    }
+  } else {
+    if (Imm12)
+      Imm = getImm12(insn);
+    else
+      Imm = decodeImm8(insn);
+  }
+  
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID, R0)));
+  ++OpIdx;
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID, R1)));
+  ++OpIdx;
+
+  if (ThreeReg) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,R2)));
+    ++OpIdx;
+  }
+
+  assert(OpInfo[OpIdx].RegClass == 0 && !OpInfo[OpIdx].isPredicate()
+         && !OpInfo[OpIdx].isOptionalDef()
+         && "Pure imm operand expected");
+
+  MI.addOperand(MCOperand::CreateImm(Imm));
+  ++OpIdx;
+
+  return true;
+}
+
+// A6.3.12 Data-processing (register)
+//
+// Two register operands [rotate]:   Rs Rm [rotation(= (rotate:'000'))]
+// Three register operands only:     Rs Rn Rm
+// Three register operands [rotate]: Rs Rn Rm [rotation(= (rotate:'000'))]
+//
+// Parallel addition and subtraction 32-bit Thumb instructions: Rs Rn Rm
+//
+// Miscellaneous operations: Rs [Rn] Rm
+static bool DisassembleThumb2DPReg(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetInstrDesc &TID = ARMInsts[Opcode];
+  const TargetOperandInfo *OpInfo = TID.OpInfo;
+  unsigned &OpIdx = NumOpsAdded;
+
+  OpIdx = 0;
+
+  assert(NumOps >= 2 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 2 operands and first two as reg operands");
+
+  // Build the register operands, followed by the optional rotation amount.
+
+  bool ThreeReg = NumOps > 2 && OpInfo[2].RegClass == ARM::GPRRegClassID;
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+  ++OpIdx;
+
+  if (ThreeReg) {
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRn(insn))));
+    ++OpIdx;
+  }
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+  ++OpIdx;
+
+  if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == 0
+      && !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
+    // Add the rotation amount immediate.
+    MI.addOperand(MCOperand::CreateImm(decodeRotate(insn)));
+    ++OpIdx;
+  }
+
+  return true;
+}
+
+// A6.3.16 Multiply, multiply accumulate, and absolute difference
+//
+// t2MLA, t2MLS, t2SMMLA, t2SMMLS: Rs Rn Rm Ra=Inst{15-12}
+// t2MUL, t2SMMUL:                 Rs Rn Rm
+// t2SMLA[BB|BT|TB|TT|WB|WT]:      Rs Rn Rm Ra=Inst{15-12}
+// t2SMUL[BB|BT|TB|TT|WB|WT]:      Rs Rn Rm
+//
+// Dual halfword multiply: t2SMUAD[X], t2SMUSD[X], t2SMLAD[X], t2SMLSD[X]:
+//   Rs Rn Rm Ra=Inst{15-12}
+//
+// Unsigned Sum of Absolute Differences [and Accumulate]
+//    Rs Rn Rm [Ra=Inst{15-12}]
+static bool DisassembleThumb2Mul(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         OpInfo[2].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 3 operands and first three as reg operands");
+
+  // Build the register operands.
+
+  bool FourReg = NumOps > 3 && OpInfo[3].RegClass == ARM::GPRRegClassID;
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+
+  if (FourReg)
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+
+  NumOpsAdded = FourReg ? 4 : 3;
+
+  return true;
+}
+
+// A6.3.17 Long multiply, long multiply accumulate, and divide
+//
+// t2SMULL, t2UMULL, t2SMLAL, t2UMLAL, t2UMAAL: RdLo RdHi Rn Rm
+// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
+//
+// Halfword multiple accumulate long: t2SMLAL<x><y>: RdLo RdHi Rn Rm
+// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
+//
+// Dual halfword multiple: t2SMLALD[X], t2SMLSLD[X]: RdLo RdHi Rn Rm
+// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
+//
+// Signed/Unsigned divide: t2SDIV, t2UDIV: Rs Rn Rm
+static bool DisassembleThumb2LongMul(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  const TargetOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
+
+  assert(NumOps >= 3 &&
+         OpInfo[0].RegClass == ARM::GPRRegClassID &&
+         OpInfo[1].RegClass == ARM::GPRRegClassID &&
+         OpInfo[2].RegClass == ARM::GPRRegClassID &&
+         "Expect >= 3 operands and first three as reg operands");
+
+  bool FourReg = NumOps > 3 && OpInfo[3].RegClass == ARM::GPRRegClassID;
+
+  // Build the register operands.
+
+  if (FourReg)
+    MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                       decodeRd(insn))));
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRs(insn))));
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRn(insn))));
+
+  MI.addOperand(MCOperand::CreateReg(getRegisterEnum(ARM::GPRRegClassID,
+                                                     decodeRm(insn))));
+
+  if (FourReg)
+    NumOpsAdded = 4;
+  else
+    NumOpsAdded = 3;
+
+  return true;
+}
+
+// See A6.3 32-bit Thumb instruction encoding for instruction classes
+// corresponding to (op1, op2, op).
+//
+// Table A6-9 32-bit Thumb instruction encoding
+// op1	op2		op	Instruction class, see
+// ---	-------	--	------------------------------------------------------------
+// 01	00xx0xx	-	Load/store multiple on page A6-23
+// 		00xx1xx	-	Load/store dual, load/store exclusive, table branch on page A6-24
+// 		01xxxxx	-	Data-processing (shifted register) on page A6-31
+// 		1xxxxxx	-	Coprocessor instructions on page A6-40
+// 10	x0xxxxx	0	Data-processing (modified immediate) on page A6-15
+// 		x1xxxxx	0	Data-processing (plain binary immediate) on page A6-19
+// 		-		1	Branches and miscellaneous control on page A6-20
+// 11	000xxx0	-	Store single data item on page A6-30
+// 		001xxx0	-	Advanced SIMD element or structure load/store instructions on page A7-27
+// 		00xx001 -	Load byte, memory hints on page A6-28
+// 		00xx011	-	Load halfword, memory hints on page A6-26
+// 		00xx101	-	Load word on page A6-25
+// 		00xx111	-	UNDEFINED
+// 		010xxxx	-	Data-processing (register) on page A6-33
+// 		0110xxx	-	Multiply, multiply accumulate, and absolute difference on page A6-38
+// 		0111xxx	-	Long multiply, long multiply accumulate, and divide on page A6-39
+// 		1xxxxxx	-	Coprocessor instructions on page A6-40
+//
+static bool DisassembleThumb2(uint16_t op1, uint16_t op2, uint16_t op,
+    MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded) {
+
+  switch (op1) {
+  case 1:
+    if (slice(op2, 6, 5) == 0) {
+      if (slice(op2, 2, 2) == 0) {
+        // Load/store multiple.
+        return DisassembleThumb2LdStMul(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+
+      // Load/store dual, load/store exclusive, table branch, otherwise.
+      assert(slice(op2, 2, 2) == 1 && "Encoding error");
+      if ((ARM::t2LDREX <= Opcode && Opcode <= ARM::t2LDREXH) ||
+          (ARM::t2STREX <= Opcode && Opcode <= ARM::t2STREXH)) {
+        // Load/store exclusive.
+        return DisassembleThumb2LdStEx(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+      if (Opcode == ARM::t2LDRDi8 ||
+          Opcode == ARM::t2LDRD_PRE || Opcode == ARM::t2LDRD_POST ||
+          Opcode == ARM::t2STRDi8 ||
+          Opcode == ARM::t2STRD_PRE || Opcode == ARM::t2STRD_POST) {
+        // Load/store dual.
+        return DisassembleThumb2LdStDual(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+      if (Opcode == ARM::t2TBBgen || Opcode == ARM::t2TBHgen) {
+        // Table branch.
+        return DisassembleThumb2TB(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+    } else if (slice(op2, 6, 5) == 1) {
+      // Data-processing (shifted register).
+      return DisassembleThumb2DPSoReg(MI, Opcode, insn, NumOps, NumOpsAdded);
+    }
+
+    // FIXME: A6.3.18 Coprocessor instructions
+    // But see ThumbDisassembler::getInstruction().
+
+    break;
+  case 2:
+    if (op == 0) {
+      if (slice(op2, 5, 5) == 0) {
+        // Data-processing (modified immediate)
+        return DisassembleThumb2DPModImm(MI, Opcode, insn, NumOps, NumOpsAdded);
+      } else {
+        // Data-processing (plain binary immediate)
+        return DisassembleThumb2DPBinImm(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+    } else {
+      // Branches and miscellaneous control on page A6-20.
+      return DisassembleThumb2BrMiscCtrl(MI, Opcode, insn, NumOps, NumOpsAdded);
+    }
+
+    break;
+  case 3:
+    switch (slice(op2, 6, 5)) {
+    case 0:
+      // Load/store instructions...
+      if (slice(op2, 0, 0) == 0) {
+        if (slice(op2, 4, 4) == 0) {
+          // Store single data item on page A6-30
+          return DisassembleThumb2LdSt(false, MI,Opcode,insn,NumOps,NumOpsAdded);
+        } else {
+          // FIXME: Advanced SIMD element or structure load/store instructions.
+          // But see ThumbDisassembler::getInstruction().
+          ;
+        }
+      } else {
+        // Table A6-9 32-bit Thumb instruction encoding: Load byte|halfword|word
+        return DisassembleThumb2LdSt(true, MI,Opcode,insn,NumOps,NumOpsAdded);
+      }
+      break;
+    case 1:
+      if (slice(op2, 4, 4) == 0) {
+        // A6.3.12 Data-processing (register)
+        return DisassembleThumb2DPReg(MI, Opcode, insn, NumOps, NumOpsAdded);
+      } else if (slice(op2, 3, 3) == 0) {
+        // A6.3.16 Multiply, multiply accumulate, and absolute difference
+        return DisassembleThumb2Mul(MI, Opcode, insn, NumOps, NumOpsAdded);
+      } else {
+        // A6.3.17 Long multiply, long multiply accumulate, and divide
+        return DisassembleThumb2LongMul(MI, Opcode, insn, NumOps, NumOpsAdded);
+      }
+      break;
+    default:
+      // FIXME: A6.3.18 Coprocessor instructions
+      // But see ThumbDisassembler::getInstruction().
+      ;
+      break;
+    }
+
+    break;
+  default:
+    assert(0 && "Encoding error for Thumb2 instruction!");
+    break;
+  }
+
+  return false;
+}
+
+static bool DisassembleThumbFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
+    unsigned short NumOps, unsigned &NumOpsAdded, BO Builder) {
+
+  uint16_t HalfWord = slice(insn, 31, 16);
+
+  if (HalfWord == 0) {
+    // A6.2 16-bit Thumb instruction encoding
+    // op = bits[15:10]
+    uint16_t op = slice(insn, 15, 10);
+    return DisassembleThumb1(op, MI, Opcode, insn, NumOps, NumOpsAdded,
+                             Builder);
+  }
+
+  unsigned bits15_11 = slice(HalfWord, 15, 11);
+
+  // A6.1 Thumb instruction set encoding
+  assert((bits15_11 == 0x1D || bits15_11 == 0x1E || bits15_11 == 0x1F) &&
+         "Bits [15:11] of first halfword of a Thumb2 instruction out of range");
+
+  // A6.3 32-bit Thumb instruction encoding
+  
+  uint16_t op1 = slice(HalfWord, 12, 11);
+  uint16_t op2 = slice(HalfWord, 10, 4);
+  uint16_t op = slice(insn, 15, 15);
+
+  return DisassembleThumb2(op1, op2, op, MI, Opcode, insn, NumOps, NumOpsAdded);
+}

Modified: llvm/trunk/lib/Target/ARM/Makefile
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Makefile?rev=100233&r1=100232&r2=100233&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Makefile (original)
+++ llvm/trunk/lib/Target/ARM/Makefile Fri Apr  2 17:27:38 2010
@@ -16,8 +16,9 @@
                 ARMGenRegisterInfo.inc ARMGenInstrNames.inc \
                 ARMGenInstrInfo.inc ARMGenAsmWriter.inc \
                 ARMGenDAGISel.inc ARMGenSubtarget.inc \
-                ARMGenCodeEmitter.inc ARMGenCallingConv.inc
+                ARMGenCodeEmitter.inc ARMGenCallingConv.inc \
+		ARMGenDecoderTables.inc
 
-DIRS = AsmPrinter AsmParser TargetInfo
+DIRS = AsmPrinter AsmParser Disassembler TargetInfo
 
 include $(LEVEL)/Makefile.common

Added: llvm/trunk/test/MC/Disassembler/arm-tests.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/arm-tests.txt?rev=100233&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/arm-tests.txt (added)
+++ llvm/trunk/test/MC/Disassembler/arm-tests.txt Fri Apr  2 17:27:38 2010
@@ -0,0 +1,62 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 | FileCheck %s
+
+# CHECK:	b	#0
+0xfe 0xff 0xff 0xea
+
+# CHECK:	bfc	r8, #0, #16
+0x1f 0x80 0xcf 0xe7
+
+# CHECK:	bfi	r8, r0, #16, #1
+0x10 0x88 0xd0 0xe7
+
+# CHECK:	cmn	r0, #1
+0x01 0x00 0x70 0xe3
+
+# CHECK:	dmb	nshst
+0x56 0xf0 0x7f 0xf5
+
+# CHECK:	ldr	r0, [r2], #15
+0x0f 0x00 0x92 0xe4
+
+# CHECK:	lsls	r0, r2, #31
+0x82 0x0f 0xb0 0xe1
+
+# CHECK:	mcr2	p0, #0, r2, cr1, cr0, #7
+0xf0 0x20 0x01 0xfe
+
+# CHECK:	movt	r8, #65535
+0xff 0x8f 0x4f 0xe3
+
+# CHECK:	pkhbt	r8, r9, r10, lsl #4
+0x1a 0x82 0x89 0xe6
+
+# CHECK:	pop	{r0, r2, r4, r6, r8, r10}
+0x55 0x05 0xbd 0xe8
+
+# CHECK:	push	{r0, r2, r4, r6, r8, r10}
+0x55 0x05 0x2d 0xe9
+
+# CHECK:	qsax	r8, r9, r10
+0x5a 0x8f 0x29 0xe6
+
+# CHECK:	rfedb	r0!
+0x00 0x0a 0x30 0xf9
+
+# CHECK:	sbcs	r0, pc, #1
+0x01 0x00 0xdf 0xe2
+
+# CHECK:	sbfx	r0, r1, #0, #8
+0x51 0x00 0xa7 0xe7
+
+# CHECK:	ssat	r8, #1, r10, lsl #8
+0x1a 0x84 0xa0 0xe6
+
+# CHECK:	stmdb	r10!, {r4, r5, r6, r7, lr}
+0xf0 0x40 0x2a 0xe9
+
+# CHECK:	teq	r0, #31
+0x1f 0x00 0x30 0xe3
+
+# CHECK:	ubfx	r0, r0, #16, #1
+0x50 0x08 0xe0 0xe7
+

Added: llvm/trunk/test/MC/Disassembler/neon-tests.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/neon-tests.txt?rev=100233&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/neon-tests.txt (added)
+++ llvm/trunk/test/MC/Disassembler/neon-tests.txt Fri Apr  2 17:27:38 2010
@@ -0,0 +1,41 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 | FileCheck %s
+
+# CHECK:	vbif	q15, q7, q0
+0x50 0xe1 0x7e 0xf3
+
+# CHECK:	vcvt.f32.s32	q15, q0, #1
+0x50 0xee 0xff 0xf2
+
+# CHECK:	vdup.32	q3, d1[0]
+0x41 0x6c 0xb4 0xf3
+
+# CHECK:	vld4.8	{d0, d1, d2, d3}, [r2], r7
+0x07 0x00 0x22 0xf4
+
+# CHECK:	vld4.8	{d4, d6, d8, d10}, [r2]
+0x0f 0x41 0x22 0xf4
+
+# CHECK:	vmov	d0, d15
+0x1f 0x01 0x2f 0xf2
+
+# CHECK:	vmul.f32	d0, d0, d6
+0x16 0x0d 0x00 0xf3
+
+# CHECK:	vneg.f32	q0, q0
+0xc0 0x07 0xb9 0xf3
+
+# CHECK:	vqrdmulh.s32	d0, d0, d3[1]
+0x63 0x0d 0xa0 0xf2
+
+# CHECK:	vrshr.s32	d0, d0, #16
+0x10 0x02 0xb0 0xf2
+
+# CHECK:	vshll.i16	q3, d1, #16
+0x01 0x63 0xb6 0xf3
+
+# CHECK:	vsri.32	q15, q0, #1
+0x50 0xe4 0xff 0xf3
+
+# CHECK:	vtbx.8	d18, {d4, d5, d6}, d7
+0x47 0x2a 0xf4 0xf3
+

Added: llvm/trunk/test/MC/Disassembler/thumb-tests.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/thumb-tests.txt?rev=100233&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/thumb-tests.txt (added)
+++ llvm/trunk/test/MC/Disassembler/thumb-tests.txt Fri Apr  2 17:27:38 2010
@@ -0,0 +1,81 @@
+# RUN: llvm-mc --disassemble %s -triple=thumb-apple-darwin9 | FileCheck %s
+
+# CHECK:	add	r5, sp, #68
+0x11 0xad
+
+# CHECK:	adcs	r0, r0, #1
+0x50 0xf1 0x01 0x00
+
+# CHECK:	b	#34
+0x0f 0xe0
+
+# CHECK:	bfi	r2, r10, #0, #1
+0x6a 0xf3 0x00 0x02
+
+# CHECK:	cbnz	r7, #20
+0x57 0xb9
+
+# CHECK:	cmp	r3, r4
+0xa3 0x42
+
+# CHECK:	cmn.w	r0, #31
+0x10 0xf1 0x1f 0x0f
+
+# CHECK:	ldmia	r0!, {r1}
+0x02 0xc8
+
+# CHECK:	ldrd	r0, r1, [r7, #64]!
+0xf7 0xe9 0x10 0x01
+
+# CHECK:	lsls.w	r0, pc, #1
+0x5f 0xea 0x4f 0x00
+
+# CHECK:	mov	r11, r7
+0xbb 0x46
+
+# CHECK:	pkhtb	r2, r4, r6, asr #16
+0xc4 0xea 0x26 0x42
+
+# CHECK:	pop	{r2, r4, r6, r8, r10, r12}
+0xbd 0xe8 0x54 0x15
+
+# CHECK:	push	{r2, r4, r6, r8, r10, r12}
+0x2d 0xe9 0x54 0x15
+
+# CHECK:	rsbs	r0, r0, #0
+0x40 0x42
+
+# CHECK:	strd	r0, [r7, #64]
+0xc7 0xe9 0x10 0x01
+
+# CHECK:	sub	sp, #60
+0x8f 0xb0
+
+# CHECK:	subw	r0, pc, #1
+0xaf 0xf2 0x01 0x00
+
+# CHECK:	uqadd16	r3, r4, r5
+0x94 0xfa 0x55 0xf3
+
+# CHECK:	usada8	r5, r4, r3, r2
+0x74 0xfb 0x03 0x25
+
+# CHECK:	uxtab16	r1, r2, r3, ror #8
+0x32 0xfa 0x93 0xf1
+
+# IT block begin
+# CHECK:	ittte	eq
+0x03 0xbf
+
+# CHECK:	moveq	r3, #3
+0x03 0x23
+
+# CHECK:	asreq	r1, r0, #5
+0x41 0x11
+
+# CHECK:	lsleq	r1, r0, #28
+0x01 0x07
+
+# CHECK:	rsbne	r1, r2, #0
+0x51 0x42
+# IT block end

Added: llvm/trunk/utils/TableGen/ARMDecoderEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/ARMDecoderEmitter.cpp?rev=100233&view=auto
==============================================================================
--- llvm/trunk/utils/TableGen/ARMDecoderEmitter.cpp (added)
+++ llvm/trunk/utils/TableGen/ARMDecoderEmitter.cpp Fri Apr  2 17:27:38 2010
@@ -0,0 +1,1861 @@
+//===------------ ARMDecoderEmitter.cpp - Decoder Generator ---------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains the tablegen backend that emits the decoder functions for ARM and
+// Thumb.  The disassembler core includes the auto-generated file, invokes the
+// decoder functions, and builds up the MCInst based on the decoded Opcode.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "arm-decoder-emitter"
+
+#include "ARMDecoderEmitter.h"
+#include "CodeGenTarget.h"
+#include "Record.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <vector>
+#include <map>
+#include <string>
+
+using namespace llvm;
+
+/////////////////////////////////////////////////////
+//                                                 //
+//  Enums and Utilities for ARM Instruction Format //
+//                                                 //
+/////////////////////////////////////////////////////
+
+#define ARM_FORMATS                   \
+  ENTRY(ARM_FORMAT_PSEUDO,         0) \
+  ENTRY(ARM_FORMAT_MULFRM,         1) \
+  ENTRY(ARM_FORMAT_BRFRM,          2) \
+  ENTRY(ARM_FORMAT_BRMISCFRM,      3) \
+  ENTRY(ARM_FORMAT_DPFRM,          4) \
+  ENTRY(ARM_FORMAT_DPSOREGFRM,     5) \
+  ENTRY(ARM_FORMAT_LDFRM,          6) \
+  ENTRY(ARM_FORMAT_STFRM,          7) \
+  ENTRY(ARM_FORMAT_LDMISCFRM,      8) \
+  ENTRY(ARM_FORMAT_STMISCFRM,      9) \
+  ENTRY(ARM_FORMAT_LDSTMULFRM,    10) \
+  ENTRY(ARM_FORMAT_LDSTEXFRM,     11) \
+  ENTRY(ARM_FORMAT_ARITHMISCFRM,  12) \
+  ENTRY(ARM_FORMAT_EXTFRM,        13) \
+  ENTRY(ARM_FORMAT_VFPUNARYFRM,   14) \
+  ENTRY(ARM_FORMAT_VFPBINARYFRM,  15) \
+  ENTRY(ARM_FORMAT_VFPCONV1FRM,   16) \
+  ENTRY(ARM_FORMAT_VFPCONV2FRM,   17) \
+  ENTRY(ARM_FORMAT_VFPCONV3FRM,   18) \
+  ENTRY(ARM_FORMAT_VFPCONV4FRM,   19) \
+  ENTRY(ARM_FORMAT_VFPCONV5FRM,   20) \
+  ENTRY(ARM_FORMAT_VFPLDSTFRM,    21) \
+  ENTRY(ARM_FORMAT_VFPLDSTMULFRM, 22) \
+  ENTRY(ARM_FORMAT_VFPMISCFRM,    23) \
+  ENTRY(ARM_FORMAT_THUMBFRM,      24) \
+  ENTRY(ARM_FORMAT_NEONFRM,       25) \
+  ENTRY(ARM_FORMAT_NEONGETLNFRM,  26) \
+  ENTRY(ARM_FORMAT_NEONSETLNFRM,  27) \
+  ENTRY(ARM_FORMAT_NEONDUPFRM,    28) \
+  ENTRY(ARM_FORMAT_MISCFRM,       29) \
+  ENTRY(ARM_FORMAT_THUMBMISCFRM,  30) \
+  ENTRY(ARM_FORMAT_NLdSt,         31) \
+  ENTRY(ARM_FORMAT_N1RegModImm,   32) \
+  ENTRY(ARM_FORMAT_N2Reg,         33) \
+  ENTRY(ARM_FORMAT_NVCVT,         34) \
+  ENTRY(ARM_FORMAT_NVecDupLn,     35) \
+  ENTRY(ARM_FORMAT_N2RegVecShL,   36) \
+  ENTRY(ARM_FORMAT_N2RegVecShR,   37) \
+  ENTRY(ARM_FORMAT_N3Reg,         38) \
+  ENTRY(ARM_FORMAT_N3RegVecSh,    39) \
+  ENTRY(ARM_FORMAT_NVecExtract,   40) \
+  ENTRY(ARM_FORMAT_NVecMulScalar, 41) \
+  ENTRY(ARM_FORMAT_NVTBL,         42)
+
+// ARM instruction format specifies the encoding used by the instruction.
+#define ENTRY(n, v) n = v,
+typedef enum {
+  ARM_FORMATS
+  ARM_FORMAT_NA
+} ARMFormat;
+#undef ENTRY
+
+// Converts enum to const char*.
+static const char *stringForARMFormat(ARMFormat form) {
+#define ENTRY(n, v) case n: return #n;
+  switch(form) {
+    ARM_FORMATS
+  case ARM_FORMAT_NA:
+  default:
+    return "";
+  }
+#undef ENTRY
+}
+
+typedef enum {
+  IndexModeNone = 0,
+  IndexModePre  = 1,
+  IndexModePost = 2,
+  IndexModeUpd  = 3
+};
+
+/////////////////////////
+//                     //
+//  Utility functions  //
+//                     //
+/////////////////////////
+
+/// byteFromBitsInit - Return the byte value from a BitsInit.
+/// Called from getByteField().
+static uint8_t byteFromBitsInit(BitsInit &init) {
+  int width = init.getNumBits();
+
+  assert(width <= 8 && "Field is too large for uint8_t!");
+
+  int index;
+  uint8_t mask = 0x01;
+
+  uint8_t ret = 0;
+
+  for (index = 0; index < width; index++) {
+    if (static_cast<BitInit*>(init.getBit(index))->getValue())
+      ret |= mask;
+
+    mask <<= 1;
+  }
+
+  return ret;
+}
+
+static uint8_t getByteField(const Record &def, const char *str) {
+  BitsInit *bits = def.getValueAsBitsInit(str);
+  return byteFromBitsInit(*bits);
+}
+
+static BitsInit &getBitsField(const Record &def, const char *str) {
+  BitsInit *bits = def.getValueAsBitsInit(str);
+  return *bits;
+}
+
+/// sameStringExceptSuffix - Return true if the two strings differ only in RHS's
+/// suffix.  ("VST4d8", "VST4d8_UPD", "_UPD") as input returns true.
+static
+bool sameStringExceptSuffix(const StringRef LHS, const StringRef RHS,
+                            const StringRef Suffix) {
+
+  if (RHS.startswith(LHS) && RHS.endswith(Suffix))
+    return RHS.size() == LHS.size() + Suffix.size();
+
+  return false;
+}
+
+/// thumbInstruction - Determine whether we have a Thumb instruction.
+/// See also ARMInstrFormats.td.
+static bool thumbInstruction(uint8_t Form) {
+  return Form == ARM_FORMAT_THUMBFRM;
+}
+
+// The set (BIT_TRUE, BIT_FALSE, BIT_UNSET) represents a ternary logic system
+// for a bit value.
+//
+// BIT_UNFILTERED is used as the init value for a filter position.  It is used
+// only for filter processings.
+typedef enum {
+  BIT_TRUE,      // '1'
+  BIT_FALSE,     // '0'
+  BIT_UNSET,     // '?'
+  BIT_UNFILTERED // unfiltered
+} bit_value_t;
+
+static bool ValueSet(bit_value_t V) {
+  return (V == BIT_TRUE || V == BIT_FALSE);
+}
+static bool ValueNotSet(bit_value_t V) {
+  return (V == BIT_UNSET);
+}
+static int Value(bit_value_t V) {
+  return ValueNotSet(V) ? -1 : (V == BIT_FALSE ? 0 : 1);
+}
+static bit_value_t bitFromBits(BitsInit &bits, unsigned index) {
+  if (BitInit *bit = dynamic_cast<BitInit*>(bits.getBit(index)))
+    return bit->getValue() ? BIT_TRUE : BIT_FALSE;
+
+  // The bit is uninitialized.
+  return BIT_UNSET;
+}
+// Prints the bit value for each position.
+static void dumpBits(raw_ostream &o, BitsInit &bits) {
+  unsigned index;
+
+  for (index = bits.getNumBits(); index > 0; index--) {
+    switch (bitFromBits(bits, index - 1)) {
+    case BIT_TRUE:
+      o << "1";
+      break;
+    case BIT_FALSE:
+      o << "0";
+      break;
+    case BIT_UNSET:
+      o << "_";
+      break;
+    default:
+      assert(0 && "unexpected return value from bitFromBits");
+    }
+  }
+}
+
+// Enums for the available target names.
+typedef enum {
+  TARGET_ARM = 0,
+  TARGET_THUMB
+} TARGET_NAME_t;
+
+// FIXME: Possibly auto-detected?
+#define BIT_WIDTH 32
+
+// Forward declaration.
+class FilterChooser;
+
+// Representation of the instruction to work on.
+typedef bit_value_t insn_t[BIT_WIDTH];
+
+/// Filter - Filter works with FilterChooser to produce the decoding tree for
+/// the ISA.
+///
+/// It is useful to think of a Filter as governing the switch stmts of the
+/// decoding tree in a certain level.  Each case stmt delegates to an inferior
+/// FilterChooser to decide what further decoding logic to employ, or in another
+/// words, what other remaining bits to look at.  The FilterChooser eventually
+/// chooses a best Filter to do its job.
+///
+/// This recursive scheme ends when the number of Opcodes assigned to the
+/// FilterChooser becomes 1 or if there is a conflict.  A conflict happens when
+/// the Filter/FilterChooser combo does not know how to distinguish among the
+/// Opcodes assigned.
+///
+/// An example of a conflcit is 
+///
+/// Conflict:
+///                     111101000.00........00010000....
+///                     111101000.00........0001........
+///                     1111010...00........0001........
+///                     1111010...00....................
+///                     1111010.........................
+///                     1111............................
+///                     ................................
+///     VST4q8a         111101000_00________00010000____
+///     VST4q8b         111101000_00________00010000____
+///
+/// The Debug output shows the path that the decoding tree follows to reach the
+/// the conclusion that there is a conflict.  VST4q8a is a vst4 to double-spaced
+/// even registers, while VST4q8b is a vst4 to double-spaced odd regsisters.
+///
+/// The encoding info in the .td files does not specify this meta information,
+/// which could have been used by the decoder to resolve the conflict.  The
+/// decoder could try to decode the even/odd register numbering and assign to
+/// VST4q8a or VST4q8b, but for the time being, the decoder chooses the "a"
+/// version and return the Opcode since the two have the same Asm format string.
+class Filter {
+protected:
+  FilterChooser *Owner; // points to the FilterChooser who owns this filter
+  unsigned StartBit; // the starting bit position
+  unsigned NumBits; // number of bits to filter
+  bool Mixed; // a mixed region contains both set and unset bits
+
+  // Map of well-known segment value to the set of uid's with that value. 
+  std::map<uint64_t, std::vector<unsigned> > FilteredInstructions;
+
+  // Set of uid's with non-constant segment values.
+  std::vector<unsigned> VariableInstructions;
+
+  // Map of well-known segment value to its delegate.
+  std::map<unsigned, FilterChooser*> FilterChooserMap;
+
+  // Number of instructions which fall under FilteredInstructions category.
+  unsigned NumFiltered;
+
+  // Keeps track of the last opcode in the filtered bucket.
+  unsigned LastOpcFiltered;
+
+  // Number of instructions which fall under VariableInstructions category.
+  unsigned NumVariable;
+
+public:
+  unsigned getNumFiltered() { return NumFiltered; }
+  unsigned getNumVariable() { return NumVariable; }
+  unsigned getSingletonOpc() {
+    assert(NumFiltered == 1);
+    return LastOpcFiltered;
+  }
+  // Return the filter chooser for the group of instructions without constant
+  // segment values.
+  FilterChooser &getVariableFC() {
+    assert(NumFiltered == 1);
+    assert(FilterChooserMap.size() == 1);
+    return *(FilterChooserMap.find(-1)->second);
+  }
+
+  Filter(const Filter &f);
+  Filter(FilterChooser &owner, unsigned startBit, unsigned numBits, bool mixed);
+
+  ~Filter();
+
+  // Divides the decoding task into sub tasks and delegates them to the
+  // inferior FilterChooser's.
+  //
+  // A special case arises when there's only one entry in the filtered
+  // instructions.  In order to unambiguously decode the singleton, we need to
+  // match the remaining undecoded encoding bits against the singleton.
+  void recurse();
+
+  // Emit code to decode instructions given a segment or segments of bits.
+  void emit(raw_ostream &o, unsigned &Indentation);
+
+  // Returns the number of fanout produced by the filter.  More fanout implies
+  // the filter distinguishes more categories of instructions.
+  unsigned usefulness() const;
+}; // End of class Filter
+
+// These are states of our finite state machines used in FilterChooser's
+// filterProcessor() which produces the filter candidates to use.
+typedef enum {
+  ATTR_NONE,
+  ATTR_FILTERED,
+  ATTR_ALL_SET,
+  ATTR_ALL_UNSET,
+  ATTR_MIXED
+} bitAttr_t;
+
+/// FilterChooser - FilterChooser chooses the best filter among a set of Filters
+/// in order to perform the decoding of instructions at the current level.
+///
+/// Decoding proceeds from the top down.  Based on the well-known encoding bits
+/// of instructions available, FilterChooser builds up the possible Filters that
+/// can further the task of decoding by distinguishing among the remaining
+/// candidate instructions.
+///
+/// Once a filter has been chosen, it is called upon to divide the decoding task
+/// into sub-tasks and delegates them to its inferior FilterChoosers for further
+/// processings.
+///
+/// It is useful to think of a Filter as governing the switch stmts of the
+/// decoding tree.  And each case is delegated to an inferior FilterChooser to
+/// decide what further remaining bits to look at.
+class FilterChooser {
+  static TARGET_NAME_t TargetName;
+
+protected:
+  friend class Filter;
+
+  // Vector of codegen instructions to choose our filter.
+  const std::vector<const CodeGenInstruction*> &AllInstructions;
+
+  // Vector of uid's for this filter chooser to work on.
+  const std::vector<unsigned> Opcodes;
+
+  // Vector of candidate filters.
+  std::vector<Filter> Filters;
+
+  // Array of bit values passed down from our parent.
+  // Set to all BIT_UNFILTERED's for Parent == NULL.
+  bit_value_t FilterBitValues[BIT_WIDTH];
+
+  // Links to the FilterChooser above us in the decoding tree.
+  FilterChooser *Parent;
+  
+  // Index of the best filter from Filters.
+  int BestIndex;
+
+public:
+  static void setTargetName(TARGET_NAME_t tn) { TargetName = tn; }
+
+  FilterChooser(const FilterChooser &FC) :
+      AllInstructions(FC.AllInstructions), Opcodes(FC.Opcodes),
+      Filters(FC.Filters), Parent(FC.Parent), BestIndex(FC.BestIndex) {
+    memcpy(FilterBitValues, FC.FilterBitValues, sizeof(FilterBitValues));
+  }
+
+  FilterChooser(const std::vector<const CodeGenInstruction*> &Insts,
+                const std::vector<unsigned> &IDs) :
+      AllInstructions(Insts), Opcodes(IDs), Filters(), Parent(NULL),
+      BestIndex(-1) {
+    for (unsigned i = 0; i < BIT_WIDTH; ++i)
+      FilterBitValues[i] = BIT_UNFILTERED;
+
+    doFilter();
+  }
+
+  FilterChooser(const std::vector<const CodeGenInstruction*> &Insts,
+                const std::vector<unsigned> &IDs,
+                bit_value_t (&ParentFilterBitValues)[BIT_WIDTH],
+                FilterChooser &parent) :
+      AllInstructions(Insts), Opcodes(IDs), Filters(), Parent(&parent),
+      BestIndex(-1) {
+    for (unsigned i = 0; i < BIT_WIDTH; ++i)
+      FilterBitValues[i] = ParentFilterBitValues[i];
+
+    doFilter();
+  }
+
+  // The top level filter chooser has NULL as its parent.
+  bool isTopLevel() { return Parent == NULL; }
+
+  // This provides an opportunity for target specific code emission.
+  void emitTopHook(raw_ostream &o);
+
+  // Emit the top level typedef and decodeInstruction() function.
+  void emitTop(raw_ostream &o, unsigned &Indentation);
+
+  // This provides an opportunity for target specific code emission after
+  // emitTop().
+  void emitBot(raw_ostream &o, unsigned &Indentation);
+
+protected:
+  // Populates the insn given the uid.
+  void insnWithID(insn_t &Insn, unsigned Opcode) const {
+    BitsInit &Bits = getBitsField(*AllInstructions[Opcode]->TheDef, "Inst");
+
+    for (unsigned i = 0; i < BIT_WIDTH; ++i)
+      Insn[i] = bitFromBits(Bits, i);
+
+    // Set Inst{21} to 1 (wback) when IndexModeBits == IndexModeUpd.
+    if (getByteField(*AllInstructions[Opcode]->TheDef, "IndexModeBits")
+        == IndexModeUpd)
+      Insn[21] = BIT_TRUE;
+  }
+
+  // Returns the record name.
+  const std::string &nameWithID(unsigned Opcode) const {
+    return AllInstructions[Opcode]->TheDef->getName();
+  }
+
+  // Populates the field of the insn given the start position and the number of
+  // consecutive bits to scan for.
+  //
+  // Returns false if there exists any uninitialized bit value in the range.
+  // Returns true, otherwise.
+  bool fieldFromInsn(uint64_t &Field, insn_t &Insn, unsigned StartBit,
+      unsigned NumBits) const;
+
+  /// dumpFilterArray - dumpFilterArray prints out debugging info for the given
+  /// filter array as a series of chars.
+  void dumpFilterArray(raw_ostream &o, bit_value_t (&filter)[BIT_WIDTH]);
+
+  /// dumpStack - dumpStack traverses the filter chooser chain and calls
+  /// dumpFilterArray on each filter chooser up to the top level one.
+  void dumpStack(raw_ostream &o, const char *prefix);
+
+  Filter &bestFilter() {
+    assert(BestIndex != -1 && "BestIndex not set");
+    return Filters[BestIndex];
+  }
+
+  // Called from Filter::recurse() when singleton exists.  For debug purpose.
+  void SingletonExists(unsigned Opc);
+
+  bool PositionFiltered(unsigned i) {
+    return ValueSet(FilterBitValues[i]);
+  }
+
+  // Calculates the island(s) needed to decode the instruction.
+  // This returns a lit of undecoded bits of an instructions, for example,
+  // Inst{20} = 1 && Inst{3-0} == 0b1111 represents two islands of yet-to-be
+  // decoded bits in order to verify that the instruction matches the Opcode.
+  unsigned getIslands(std::vector<unsigned> &StartBits,
+      std::vector<unsigned> &EndBits, std::vector<uint64_t> &FieldVals,
+      insn_t &Insn);
+
+  // The purpose of this function is for the API client to detect possible
+  // Load/Store Coprocessor instructions.  If the coprocessor number is of
+  // the instruction is either 10 or 11, the decoder should not report the
+  // instruction as LDC/LDC2/STC/STC2, but should match against Advanced SIMD or
+  // VFP instructions.
+  bool LdStCopEncoding1(unsigned Opc) {
+    const std::string &Name = nameWithID(Opc);
+    if (Name == "LDC_OFFSET" || Name == "LDC_OPTION" ||
+        Name == "LDC_POST" || Name == "LDC_PRE" ||
+        Name == "LDCL_OFFSET" || Name == "LDCL_OPTION" ||
+        Name == "LDCL_POST" || Name == "LDCL_PRE" ||
+        Name == "STC_OFFSET" || Name == "STC_OPTION" ||
+        Name == "STC_POST" || Name == "STC_PRE" ||
+        Name == "STCL_OFFSET" || Name == "STCL_OPTION" ||
+        Name == "STCL_POST" || Name == "STCL_PRE")
+      return true;
+    else
+      return false;
+  }
+
+  // Emits code to decode the singleton.  Return true if we have matched all the
+  // well-known bits.
+  bool emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,unsigned Opc);
+
+  // Emits code to decode the singleton, and then to decode the rest.
+  void emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,Filter &Best);
+
+  // Assign a single filter and run with it.
+  void runSingleFilter(FilterChooser &owner, unsigned startBit, unsigned numBit,
+      bool mixed);
+
+  // reportRegion is a helper function for filterProcessor to mark a region as
+  // eligible for use as a filter region.
+  void reportRegion(bitAttr_t RA, unsigned StartBit, unsigned BitIndex,
+      bool AllowMixed);
+
+  // FilterProcessor scans the well-known encoding bits of the instructions and
+  // builds up a list of candidate filters.  It chooses the best filter and
+  // recursively descends down the decoding tree.
+  bool filterProcessor(bool AllowMixed, bool Greedy = true);
+
+  // Decides on the best configuration of filter(s) to use in order to decode
+  // the instructions.  A conflict of instructions may occur, in which case we
+  // dump the conflict set to the standard error.
+  void doFilter();
+
+  // Emits code to decode our share of instructions.  Returns true if the
+  // emitted code causes a return, which occurs if we know how to decode
+  // the instruction at this level or the instruction is not decodeable.
+  bool emit(raw_ostream &o, unsigned &Indentation);
+};
+
+///////////////////////////
+//                       //
+// Filter Implmenetation //
+//                       //
+///////////////////////////
+
+Filter::Filter(const Filter &f) :
+  Owner(f.Owner), StartBit(f.StartBit), NumBits(f.NumBits), Mixed(f.Mixed),
+  FilteredInstructions(f.FilteredInstructions),
+  VariableInstructions(f.VariableInstructions),
+  FilterChooserMap(f.FilterChooserMap), NumFiltered(f.NumFiltered),
+  LastOpcFiltered(f.LastOpcFiltered), NumVariable(f.NumVariable) {
+}
+
+Filter::Filter(FilterChooser &owner, unsigned startBit, unsigned numBits,
+    bool mixed) : Owner(&owner), StartBit(startBit), NumBits(numBits),
+                  Mixed(mixed) {
+  assert(StartBit + NumBits - 1 < BIT_WIDTH);
+
+  NumFiltered = 0;
+  LastOpcFiltered = 0;
+  NumVariable = 0;
+
+  for (unsigned i = 0, e = Owner->Opcodes.size(); i != e; ++i) {
+    insn_t Insn;
+
+    // Populates the insn given the uid.
+    Owner->insnWithID(Insn, Owner->Opcodes[i]);
+
+    uint64_t Field;
+    // Scans the segment for possibly well-specified encoding bits.
+    bool ok = Owner->fieldFromInsn(Field, Insn, StartBit, NumBits);
+
+    if (ok) {
+      // The encoding bits are well-known.  Lets add the uid of the
+      // instruction into the bucket keyed off the constant field value.
+      LastOpcFiltered = Owner->Opcodes[i];
+      FilteredInstructions[Field].push_back(LastOpcFiltered);
+      ++NumFiltered;
+    } else {
+      // Some of the encoding bit(s) are unspecfied.  This contributes to
+      // one additional member of "Variable" instructions.
+      VariableInstructions.push_back(Owner->Opcodes[i]);
+      ++NumVariable;
+    }
+  }
+
+  assert((FilteredInstructions.size() + VariableInstructions.size() > 0)
+         && "Filter returns no instruction categories");
+}
+
+Filter::~Filter() {
+  std::map<unsigned, FilterChooser*>::iterator filterIterator;
+  for (filterIterator = FilterChooserMap.begin();
+       filterIterator != FilterChooserMap.end();
+       filterIterator++) {
+    delete filterIterator->second;
+  }
+}
+
+// Divides the decoding task into sub tasks and delegates them to the
+// inferior FilterChooser's.
+//
+// A special case arises when there's only one entry in the filtered
+// instructions.  In order to unambiguously decode the singleton, we need to
+// match the remaining undecoded encoding bits against the singleton.
+void Filter::recurse() {
+  std::map<uint64_t, std::vector<unsigned> >::const_iterator mapIterator;
+
+  bit_value_t BitValueArray[BIT_WIDTH];
+  // Starts by inheriting our parent filter chooser's filter bit values.
+  memcpy(BitValueArray, Owner->FilterBitValues, sizeof(BitValueArray));
+
+  unsigned bitIndex;
+
+  if (VariableInstructions.size()) {
+    // Conservatively marks each segment position as BIT_UNSET.
+    for (bitIndex = 0; bitIndex < NumBits; bitIndex++)
+      BitValueArray[StartBit + bitIndex] = BIT_UNSET;
+
+    // Delegates to an inferior filter chooser for futher processing on this
+    // group of instructions whose segment values are variable.
+    FilterChooserMap.insert(std::pair<unsigned, FilterChooser*>(
+                              (unsigned)-1,
+                              new FilterChooser(Owner->AllInstructions,
+                                                VariableInstructions,
+                                                BitValueArray,
+                                                *Owner)
+                              ));
+  }
+
+  // No need to recurse for a singleton filtered instruction.
+  // See also Filter::emit().
+  if (getNumFiltered() == 1) {
+    //Owner->SingletonExists(LastOpcFiltered);
+    assert(FilterChooserMap.size() == 1);
+    return;
+  }
+        
+  // Otherwise, create sub choosers.
+  for (mapIterator = FilteredInstructions.begin();
+       mapIterator != FilteredInstructions.end();
+       mapIterator++) {
+
+    // Marks all the segment positions with either BIT_TRUE or BIT_FALSE.
+    for (bitIndex = 0; bitIndex < NumBits; bitIndex++) {
+      if (mapIterator->first & (1 << bitIndex))
+        BitValueArray[StartBit + bitIndex] = BIT_TRUE;
+      else
+        BitValueArray[StartBit + bitIndex] = BIT_FALSE;
+    }
+
+    // Delegates to an inferior filter chooser for futher processing on this
+    // category of instructions.
+    FilterChooserMap.insert(std::pair<unsigned, FilterChooser*>(
+                              mapIterator->first,
+                              new FilterChooser(Owner->AllInstructions,
+                                                mapIterator->second,
+                                                BitValueArray,
+                                                *Owner)
+                              ));
+  }
+}
+
+// Emit code to decode instructions given a segment or segments of bits.
+void Filter::emit(raw_ostream &o, unsigned &Indentation) {
+  o.indent(Indentation) << "// Check Inst{";
+
+  if (NumBits > 1)
+    o << (StartBit + NumBits - 1) << '-';
+
+  o << StartBit << "} ...\n";
+
+  o.indent(Indentation) << "switch (fieldFromInstruction(insn, "
+                        << StartBit << ", " << NumBits << ")) {\n";
+
+  std::map<unsigned, FilterChooser*>::iterator filterIterator;
+
+  bool DefaultCase = false;
+  for (filterIterator = FilterChooserMap.begin();
+       filterIterator != FilterChooserMap.end();
+       filterIterator++) {
+
+    // Field value -1 implies a non-empty set of variable instructions.
+    // See also recurse().
+    if (filterIterator->first == (unsigned)-1) {
+      DefaultCase = true;
+
+      o.indent(Indentation) << "default:\n";
+      o.indent(Indentation) << "  break; // fallthrough\n";
+
+      // Closing curly brace for the switch statement.
+      // This is unconventional because we want the default processing to be
+      // performed for the fallthrough cases as well, i.e., when the "cases"
+      // did not prove a decoded instruction.
+      o.indent(Indentation) << "}\n";
+
+    } else
+      o.indent(Indentation) << "case " << filterIterator->first << ":\n";
+
+    // We arrive at a category of instructions with the same segment value.
+    // Now delegate to the sub filter chooser for further decodings.
+    // The case may fallthrough, which happens if the remaining well-known
+    // encoding bits do not match exactly.
+    if (!DefaultCase) { ++Indentation; ++Indentation; }
+
+    bool finished = filterIterator->second->emit(o, Indentation);
+    // For top level default case, there's no need for a break statement.
+    if (Owner->isTopLevel() && DefaultCase)
+      break;
+    if (!finished)
+      o.indent(Indentation) << "break;\n";
+
+    if (!DefaultCase) { --Indentation; --Indentation; }
+  }
+
+  // If there is no default case, we still need to supply a closing brace.
+  if (!DefaultCase) {
+    // Closing curly brace for the switch statement.
+    o.indent(Indentation) << "}\n";
+  }
+}
+
+// Returns the number of fanout produced by the filter.  More fanout implies
+// the filter distinguishes more categories of instructions.
+unsigned Filter::usefulness() const {
+  if (VariableInstructions.size())
+    return FilteredInstructions.size();
+  else
+    return FilteredInstructions.size() + 1;
+}
+
+//////////////////////////////////
+//                              //
+// Filterchooser Implementation //
+//                              //
+//////////////////////////////////
+
+// Define the symbol here.
+TARGET_NAME_t FilterChooser::TargetName;
+
+// This provides an opportunity for target specific code emission.
+void FilterChooser::emitTopHook(raw_ostream &o) {
+  if (TargetName == TARGET_ARM) {
+    // Emit code that references the ARMFormat data type.
+    o << "static const ARMFormat ARMFormats[] = {\n";
+    for (unsigned i = 0, e = AllInstructions.size(); i != e; ++i) {
+      const Record &Def = *(AllInstructions[i]->TheDef);
+      const std::string &Name = Def.getName();
+      if (Def.isSubClassOf("InstARM") || Def.isSubClassOf("InstThumb"))
+        o.indent(2) << 
+          stringForARMFormat((ARMFormat)getByteField(Def, "Form"));
+      else
+        o << "  ARM_FORMAT_NA";
+
+      o << ",\t// Inst #" << i << " = " << Name << '\n';
+    }
+    o << "  ARM_FORMAT_NA\t// Unreachable.\n";
+    o << "};\n\n";
+  }
+}
+
+// Emit the top level typedef and decodeInstruction() function.
+void FilterChooser::emitTop(raw_ostream &o, unsigned &Indentation) {
+  // Run the target specific emit hook.
+  emitTopHook(o);
+
+  switch (BIT_WIDTH) {
+  case 8:
+    o.indent(Indentation) << "typedef uint8_t field_t;\n";
+    break;
+  case 16:
+    o.indent(Indentation) << "typedef uint16_t field_t;\n";
+    break;
+  case 32:
+    o.indent(Indentation) << "typedef uint32_t field_t;\n";
+    break;
+  case 64:
+    o.indent(Indentation) << "typedef uint64_t field_t;\n";
+    break;
+  default:
+    assert(0 && "Unexpected instruction size!");
+  }
+
+  o << '\n';
+
+  o.indent(Indentation) << "static field_t " <<
+    "fieldFromInstruction(field_t insn, unsigned startBit, unsigned numBits)\n";
+
+  o.indent(Indentation) << "{\n";
+
+  ++Indentation; ++Indentation;
+  o.indent(Indentation) << "assert(startBit + numBits <= " << BIT_WIDTH
+                        << " && \"Instruction field out of bounds!\");\n";
+  o << '\n';
+  o.indent(Indentation) << "field_t fieldMask;\n";
+  o << '\n';
+  o.indent(Indentation) << "if (numBits == " << BIT_WIDTH << ")\n";
+
+  ++Indentation; ++Indentation;
+  o.indent(Indentation) << "fieldMask = (field_t)-1;\n";
+  --Indentation; --Indentation;
+
+  o.indent(Indentation) << "else\n";
+
+  ++Indentation; ++Indentation;
+  o.indent(Indentation) << "fieldMask = ((1 << numBits) - 1) << startBit;\n";
+  --Indentation; --Indentation;
+
+  o << '\n';
+  o.indent(Indentation) << "return (insn & fieldMask) >> startBit;\n";
+  --Indentation; --Indentation;
+
+  o.indent(Indentation) << "}\n";
+
+  o << '\n';
+
+  o.indent(Indentation) << "static uint16_t decodeInstruction(field_t insn) {\n";
+
+  ++Indentation; ++Indentation;
+  // Emits code to decode the instructions.
+  emit(o, Indentation);
+
+  o << '\n';
+  o.indent(Indentation) << "return 0;\n";
+  --Indentation; --Indentation;
+
+  o.indent(Indentation) << "}\n";
+
+  o << '\n';
+}
+
+// This provides an opportunity for target specific code emission after
+// emitTop().
+void FilterChooser::emitBot(raw_ostream &o, unsigned &Indentation) {
+  if (TargetName != TARGET_THUMB) return;
+
+  // Emit code that decodes the Thumb ISA.
+  o.indent(Indentation)
+    << "static uint16_t decodeThumbInstruction(field_t insn) {\n";
+
+  ++Indentation; ++Indentation;
+
+  // Emits code to decode the instructions.
+  emit(o, Indentation);
+
+  o << '\n';
+  o.indent(Indentation) << "return 0;\n";
+
+  --Indentation; --Indentation;
+
+  o.indent(Indentation) << "}\n";
+}
+
+// Populates the field of the insn given the start position and the number of
+// consecutive bits to scan for.
+//
+// Returns false if and on the first uninitialized bit value encountered.
+// Returns true, otherwise.
+bool FilterChooser::fieldFromInsn(uint64_t &Field, insn_t &Insn,
+    unsigned StartBit, unsigned NumBits) const {
+  Field = 0;
+
+  for (unsigned i = 0; i < NumBits; ++i) {
+    if (Insn[StartBit + i] == BIT_UNSET)
+      return false;
+
+    if (Insn[StartBit + i] == BIT_TRUE)
+      Field = Field | (1 << i);
+  }
+
+  return true;
+}
+
+/// dumpFilterArray - dumpFilterArray prints out debugging info for the given
+/// filter array as a series of chars.
+void FilterChooser::dumpFilterArray(raw_ostream &o,
+    bit_value_t (&filter)[BIT_WIDTH]) {
+  unsigned bitIndex;
+
+  for (bitIndex = BIT_WIDTH; bitIndex > 0; bitIndex--) {
+    switch (filter[bitIndex - 1]) {
+    case BIT_UNFILTERED:
+      o << ".";
+      break;
+    case BIT_UNSET:
+      o << "_";
+      break;
+    case BIT_TRUE:
+      o << "1";
+      break;
+    case BIT_FALSE:
+      o << "0";
+      break;
+    }
+  }
+}
+
+/// dumpStack - dumpStack traverses the filter chooser chain and calls
+/// dumpFilterArray on each filter chooser up to the top level one.
+void FilterChooser::dumpStack(raw_ostream &o, const char *prefix) {
+  FilterChooser *current = this;
+
+  while (current) {
+    o << prefix;
+    dumpFilterArray(o, current->FilterBitValues);
+    o << '\n';
+    current = current->Parent;
+  }
+}
+
+// Called from Filter::recurse() when singleton exists.  For debug purpose.
+void FilterChooser::SingletonExists(unsigned Opc) {
+  insn_t Insn0;
+  insnWithID(Insn0, Opc);
+
+  errs() << "Singleton exists: " << nameWithID(Opc)
+         << " with its decoding dominating ";
+  for (unsigned i = 0; i < Opcodes.size(); ++i) {
+    if (Opcodes[i] == Opc) continue;
+    errs() << nameWithID(Opcodes[i]) << ' ';
+  }
+  errs() << '\n';
+
+  dumpStack(errs(), "\t\t");
+  for (unsigned i = 0; i < Opcodes.size(); i++) {
+    const std::string &Name = nameWithID(Opcodes[i]);
+
+    errs() << '\t' << Name << " ";
+    dumpBits(errs(),
+             getBitsField(*AllInstructions[Opcodes[i]]->TheDef, "Inst"));
+    errs() << '\n';
+  }
+}
+
+// Calculates the island(s) needed to decode the instruction.
+// This returns a list of undecoded bits of an instructions, for example,
+// Inst{20} = 1 && Inst{3-0} == 0b1111 represents two islands of yet-to-be
+// decoded bits in order to verify that the instruction matches the Opcode.
+unsigned FilterChooser::getIslands(std::vector<unsigned> &StartBits,
+    std::vector<unsigned> &EndBits, std::vector<uint64_t> &FieldVals,
+    insn_t &Insn) {
+  unsigned Num, BitNo;
+  Num = BitNo = 0;
+
+  uint64_t FieldVal = 0;
+
+  // 0: Init
+  // 1: Water (the bit value does not affect decoding)
+  // 2: Island (well-known bit value needed for decoding)
+  int State = 0;
+  int Val = -1;
+
+  for (unsigned i = 0; i < BIT_WIDTH; ++i) {
+    Val = Value(Insn[i]);
+    bool Filtered = PositionFiltered(i);
+    switch (State) {
+    default:
+      assert(0 && "Unreachable code!");
+      break;
+    case 0:
+    case 1:
+      if (Filtered || Val == -1)
+        State = 1; // Still in Water
+      else {
+        State = 2; // Into the Island
+        BitNo = 0;
+        StartBits.push_back(i);
+        FieldVal = Val;
+      }
+      break;
+    case 2:
+      if (Filtered || Val == -1) {
+        State = 1; // Into the Water
+        EndBits.push_back(i - 1);
+        FieldVals.push_back(FieldVal);
+        ++Num;
+      } else {
+        State = 2; // Still in Island
+        ++BitNo;
+        FieldVal = FieldVal | Val << BitNo;
+      }
+      break;
+    }
+  }
+  // If we are still in Island after the loop, do some housekeeping.
+  if (State == 2) {
+    EndBits.push_back(BIT_WIDTH - 1);
+    FieldVals.push_back(FieldVal);
+    ++Num;
+  }
+
+  assert(StartBits.size() == Num && EndBits.size() == Num &&
+         FieldVals.size() == Num);
+  return Num;
+}
+
+// Emits code to decode the singleton.  Return true if we have matched all the
+// well-known bits.
+bool FilterChooser::emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,
+                                         unsigned Opc) {
+  std::vector<unsigned> StartBits;
+  std::vector<unsigned> EndBits;
+  std::vector<uint64_t> FieldVals;
+  insn_t Insn;
+  insnWithID(Insn, Opc);
+
+  // This provides a good opportunity to check for possible Ld/St Coprocessor
+  // Opcode and escapes if the coproc # is either 10 or 11.  It is a NEON/VFP
+  // instruction is disguise.
+  if (TargetName == TARGET_ARM && LdStCopEncoding1(Opc)) {
+    o.indent(Indentation);
+    // A8.6.51 & A8.6.188
+    // If coproc = 0b101?, i.e, slice(insn, 11, 8) = 10 or 11, escape.
+    o << "if (fieldFromInstruction(insn, 9, 3) == 5) break; // fallthrough\n";
+  }
+
+  // Look for islands of undecoded bits of the singleton.
+  getIslands(StartBits, EndBits, FieldVals, Insn);
+
+  unsigned Size = StartBits.size();
+  unsigned I, NumBits;
+
+  // If we have matched all the well-known bits, just issue a return.
+  if (Size == 0) {
+    o.indent(Indentation) << "return " << Opc << "; // " << nameWithID(Opc)
+                          << '\n';
+    return true;
+  }
+
+  // Otherwise, there are more decodings to be done!
+
+  // Emit code to match the island(s) for the singleton.
+  o.indent(Indentation) << "// Check ";
+
+  for (I = Size; I != 0; --I) {
+    o << "Inst{" << EndBits[I-1] << '-' << StartBits[I-1] << "} ";
+    if (I > 1)
+      o << "&& ";
+    else
+      o << "for singleton decoding...\n";
+  }
+
+  o.indent(Indentation) << "if (";
+
+  for (I = Size; I != 0; --I) {
+    NumBits = EndBits[I-1] - StartBits[I-1] + 1;
+    o << "fieldFromInstruction(insn, " << StartBits[I-1] << ", " << NumBits
+      << ") == " << FieldVals[I-1];
+    if (I > 1)
+      o << " && ";
+    else
+      o << ")\n";
+  }
+
+  o.indent(Indentation) << "  return " << Opc << "; // " << nameWithID(Opc)
+                        << '\n';
+
+  return false;
+}
+
+// Emits code to decode the singleton, and then to decode the rest.
+void FilterChooser::emitSingletonDecoder(raw_ostream &o, unsigned &Indentation,
+    Filter &Best) {
+
+  unsigned Opc = Best.getSingletonOpc();
+
+  emitSingletonDecoder(o, Indentation, Opc);
+
+  // Emit code for the rest.
+  o.indent(Indentation) << "else\n";
+
+  Indentation += 2;
+  Best.getVariableFC().emit(o, Indentation);
+  Indentation -= 2;
+}
+
+// Assign a single filter and run with it.  Top level API client can initialize
+// with a single filter to start the filtering process.
+void FilterChooser::runSingleFilter(FilterChooser &owner, unsigned startBit,
+    unsigned numBit, bool mixed) {
+  Filters.clear();
+  Filter F(*this, startBit, numBit, true);
+  Filters.push_back(F);
+  BestIndex = 0; // Sole Filter instance to choose from.
+  bestFilter().recurse();
+}
+
+// reportRegion is a helper function for filterProcessor to mark a region as
+// eligible for use as a filter region.
+void FilterChooser::reportRegion(bitAttr_t RA, unsigned StartBit,
+    unsigned BitIndex, bool AllowMixed) {
+  if (RA == ATTR_MIXED && AllowMixed)
+    Filters.push_back(Filter(*this, StartBit, BitIndex - StartBit, true));   
+  else if (RA == ATTR_ALL_SET && !AllowMixed)
+    Filters.push_back(Filter(*this, StartBit, BitIndex - StartBit, false));
+}
+
+// FilterProcessor scans the well-known encoding bits of the instructions and
+// builds up a list of candidate filters.  It chooses the best filter and
+// recursively descends down the decoding tree.
+bool FilterChooser::filterProcessor(bool AllowMixed, bool Greedy) {
+  Filters.clear();
+  BestIndex = -1;
+  unsigned numInstructions = Opcodes.size();
+
+  assert(numInstructions && "Filter created with no instructions");
+
+  // No further filtering is necessary.
+  if (numInstructions == 1)
+    return true;
+
+  // Heuristics.  See also doFilter()'s "Heuristics" comment when num of
+  // instructions is 3.
+  if (AllowMixed && !Greedy) {
+    assert(numInstructions == 3);
+
+    for (unsigned i = 0; i < Opcodes.size(); ++i) {
+      std::vector<unsigned> StartBits;
+      std::vector<unsigned> EndBits;
+      std::vector<uint64_t> FieldVals;
+      insn_t Insn;
+
+      insnWithID(Insn, Opcodes[i]);
+
+      // Look for islands of undecoded bits of any instruction.
+      if (getIslands(StartBits, EndBits, FieldVals, Insn) > 0) {
+        // Found an instruction with island(s).  Now just assign a filter.
+        runSingleFilter(*this, StartBits[0], EndBits[0] - StartBits[0] + 1,
+                        true);
+        return true;
+      }
+    }
+  }
+
+  unsigned BitIndex, InsnIndex;
+
+  // We maintain BIT_WIDTH copies of the bitAttrs automaton.
+  // The automaton consumes the corresponding bit from each
+  // instruction.
+  //
+  //   Input symbols: 0, 1, and _ (unset).
+  //   States:        NONE, FILTERED, ALL_SET, ALL_UNSET, and MIXED.
+  //   Initial state: NONE.
+  //
+  // (NONE) ------- [01] -> (ALL_SET)
+  // (NONE) ------- _ ----> (ALL_UNSET)
+  // (ALL_SET) ---- [01] -> (ALL_SET)
+  // (ALL_SET) ---- _ ----> (MIXED)
+  // (ALL_UNSET) -- [01] -> (MIXED)
+  // (ALL_UNSET) -- _ ----> (ALL_UNSET)
+  // (MIXED) ------ . ----> (MIXED)
+  // (FILTERED)---- . ----> (FILTERED)
+
+  bitAttr_t bitAttrs[BIT_WIDTH];
+
+  // FILTERED bit positions provide no entropy and are not worthy of pursuing.
+  // Filter::recurse() set either BIT_TRUE or BIT_FALSE for each position.
+  for (BitIndex = 0; BitIndex < BIT_WIDTH; ++BitIndex)
+    if (FilterBitValues[BitIndex] == BIT_TRUE ||
+        FilterBitValues[BitIndex] == BIT_FALSE)
+      bitAttrs[BitIndex] = ATTR_FILTERED;
+    else
+      bitAttrs[BitIndex] = ATTR_NONE;
+
+  for (InsnIndex = 0; InsnIndex < numInstructions; ++InsnIndex) {
+    insn_t insn;
+
+    insnWithID(insn, Opcodes[InsnIndex]);
+
+    for (BitIndex = 0; BitIndex < BIT_WIDTH; ++BitIndex) {
+      switch (bitAttrs[BitIndex]) {
+      case ATTR_NONE:
+        if (insn[BitIndex] == BIT_UNSET)
+          bitAttrs[BitIndex] = ATTR_ALL_UNSET;
+        else
+          bitAttrs[BitIndex] = ATTR_ALL_SET;
+        break;
+      case ATTR_ALL_SET:
+        if (insn[BitIndex] == BIT_UNSET)
+          bitAttrs[BitIndex] = ATTR_MIXED;
+        break;
+      case ATTR_ALL_UNSET:
+        if (insn[BitIndex] != BIT_UNSET)
+          bitAttrs[BitIndex] = ATTR_MIXED;
+        break;
+      case ATTR_MIXED:
+      case ATTR_FILTERED:
+        break;
+      }
+    }
+  }
+
+  // The regionAttr automaton consumes the bitAttrs automatons' state,
+  // lowest-to-highest.
+  //
+  //   Input symbols: F(iltered), (all_)S(et), (all_)U(nset), M(ixed)
+  //   States:        NONE, ALL_SET, MIXED
+  //   Initial state: NONE
+  //
+  // (NONE) ----- F --> (NONE)
+  // (NONE) ----- S --> (ALL_SET)     ; and set region start
+  // (NONE) ----- U --> (NONE)
+  // (NONE) ----- M --> (MIXED)       ; and set region start
+  // (ALL_SET) -- F --> (NONE)        ; and report an ALL_SET region
+  // (ALL_SET) -- S --> (ALL_SET)
+  // (ALL_SET) -- U --> (NONE)        ; and report an ALL_SET region
+  // (ALL_SET) -- M --> (MIXED)       ; and report an ALL_SET region
+  // (MIXED) ---- F --> (NONE)        ; and report a MIXED region
+  // (MIXED) ---- S --> (ALL_SET)     ; and report a MIXED region
+  // (MIXED) ---- U --> (NONE)        ; and report a MIXED region
+  // (MIXED) ---- M --> (MIXED)
+
+  bitAttr_t RA = ATTR_NONE;
+  unsigned StartBit = 0;
+
+  for (BitIndex = 0; BitIndex < BIT_WIDTH; BitIndex++) {
+    bitAttr_t bitAttr = bitAttrs[BitIndex];
+
+    assert(bitAttr != ATTR_NONE && "Bit without attributes");
+
+    switch (RA) {
+    case ATTR_NONE:
+      switch (bitAttr) {
+      case ATTR_FILTERED:
+        break;
+      case ATTR_ALL_SET:
+        StartBit = BitIndex;
+        RA = ATTR_ALL_SET;
+        break;
+      case ATTR_ALL_UNSET:
+        break;
+      case ATTR_MIXED:
+        StartBit = BitIndex;
+        RA = ATTR_MIXED;
+        break;
+      default:
+        assert(0 && "Unexpected bitAttr!");
+      }
+      break;
+    case ATTR_ALL_SET:
+      switch (bitAttr) {
+      case ATTR_FILTERED:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        RA = ATTR_NONE;
+        break;
+      case ATTR_ALL_SET:
+        break;
+      case ATTR_ALL_UNSET:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        RA = ATTR_NONE;
+        break;
+      case ATTR_MIXED:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        StartBit = BitIndex;
+        RA = ATTR_MIXED;
+        break;
+      default:
+        assert(0 && "Unexpected bitAttr!");
+      }
+      break;
+    case ATTR_MIXED:
+      switch (bitAttr) {
+      case ATTR_FILTERED:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        StartBit = BitIndex;
+        RA = ATTR_NONE;
+        break;
+      case ATTR_ALL_SET:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        StartBit = BitIndex;
+        RA = ATTR_ALL_SET;
+        break;
+      case ATTR_ALL_UNSET:
+        reportRegion(RA, StartBit, BitIndex, AllowMixed);
+        RA = ATTR_NONE;
+        break;
+      case ATTR_MIXED:
+        break;
+      default:
+        assert(0 && "Unexpected bitAttr!");
+      }
+      break;
+    case ATTR_ALL_UNSET:
+      assert(0 && "regionAttr state machine has no ATTR_UNSET state");
+    case ATTR_FILTERED:
+      assert(0 && "regionAttr state machine has no ATTR_FILTERED state");
+    }
+  }
+
+  // At the end, if we're still in ALL_SET or MIXED states, report a region
+  switch (RA) {
+  case ATTR_NONE:
+    break;
+  case ATTR_FILTERED:
+    break;
+  case ATTR_ALL_SET:
+    reportRegion(RA, StartBit, BitIndex, AllowMixed);
+    break;
+  case ATTR_ALL_UNSET:
+    break;
+  case ATTR_MIXED:
+    reportRegion(RA, StartBit, BitIndex, AllowMixed);
+    break;
+  }
+
+  // We have finished with the filter processings.  Now it's time to choose
+  // the best performing filter.
+  BestIndex = 0;
+  bool AllUseless = true;
+  unsigned BestScore = 0;
+
+  for (unsigned i = 0, e = Filters.size(); i != e; ++i) {
+    unsigned Usefulness = Filters[i].usefulness();
+
+    if (Usefulness)
+      AllUseless = false;
+
+    if (Usefulness > BestScore) {
+      BestIndex = i;
+      BestScore = Usefulness;
+    }
+  }
+
+  if (!AllUseless)
+    bestFilter().recurse();
+
+  return !AllUseless;
+} // end of FilterChooser::filterProcessor(bool)
+
+// Decides on the best configuration of filter(s) to use in order to decode
+// the instructions.  A conflict of instructions may occur, in which case we
+// dump the conflict set to the standard error.
+void FilterChooser::doFilter() {
+  unsigned Num = Opcodes.size();
+  assert(Num && "FilterChooser created with no instructions");
+
+  // Heuristics: Use Inst{31-28} as the top level filter for ARM ISA.
+  if (TargetName == TARGET_ARM && Parent == NULL) {
+    runSingleFilter(*this, 28, 4, false);
+    return;
+  }
+
+  // Try regions of consecutive known bit values first. 
+  if (filterProcessor(false))
+    return;
+
+  // Then regions of mixed bits (both known and unitialized bit values allowed).
+  if (filterProcessor(true))
+    return;
+
+  // Heuristics to cope with conflict set {t2CMPrs, t2SUBSrr, t2SUBSrs} where
+  // no single instruction for the maximum ATTR_MIXED region Inst{14-4} has a
+  // well-known encoding pattern.  In such case, we backtrack and scan for the
+  // the very first consecutive ATTR_ALL_SET region and assign a filter to it.
+  if (Num == 3 && filterProcessor(true, false))
+    return;
+
+  // If we come to here, the instruction decoding has failed.
+  // Print out the instructions in the conflict set...
+  BestIndex = -1;
+
+  DEBUG({
+      errs() << "Conflict:\n";
+
+      dumpStack(errs(), "\t\t");
+
+      for (unsigned i = 0; i < Num; i++) {
+        const std::string &Name = nameWithID(Opcodes[i]);
+
+        errs() << '\t' << Name << " ";
+        dumpBits(errs(),
+                 getBitsField(*AllInstructions[Opcodes[i]]->TheDef, "Inst"));
+        errs() << '\n';
+      }
+    });
+}
+
+// Emits code to decode our share of instructions.  Returns true if the
+// emitted code causes a return, which occurs if we know how to decode
+// the instruction at this level or the instruction is not decodeable.
+bool FilterChooser::emit(raw_ostream &o, unsigned &Indentation) {
+  if (Opcodes.size() == 1)
+    // There is only one instruction in the set, which is great!
+    // Call emitSingletonDecoder() to see whether there are any remaining
+    // encodings bits.
+    return emitSingletonDecoder(o, Indentation, Opcodes[0]);
+
+  // Choose the best filter to do the decodings!
+  if (BestIndex != -1) {
+    Filter &Best = bestFilter();
+    if (Best.getNumFiltered() == 1)
+      emitSingletonDecoder(o, Indentation, Best);
+    else
+      bestFilter().emit(o, Indentation);
+    return false;
+  }
+
+  // If we reach here, there is a conflict in decoding.  Let's resolve the known
+  // conflicts!
+  if ((TargetName == TARGET_ARM || TargetName == TARGET_THUMB) &&
+      Opcodes.size() == 2) {
+    // Resolve the known conflict sets:
+    //
+    // 1. source registers are identical => VMOVDneon; otherwise => VORRd
+    // 2. source registers are identical => VMOVQ; otherwise => VORRq
+    // 3. LDR, LDRcp => return LDR for now.
+    // FIXME: How can we distinguish between LDR and LDRcp?  Do we need to?
+    // 4. tLDM, tLDM_UPD => Rn = Inst{10-8}, reglist = Inst{7-0},
+    //    wback = registers<Rn> = 0
+    // NOTE: (tLDM, tLDM_UPD) resolution must come before Advanced SIMD
+    //       addressing mode resolution!!!
+    // 5. VLD[234]LN*/VST[234]LN* vs. VLD[234]LN*_UPD/VST[234]LN*_UPD conflicts
+    //    are resolved returning the non-UPD versions of the instructions if the
+    //    Rm field, i.e., Inst{3-0} is 0b1111.  This is specified in A7.7.1
+    //    Advanced SIMD addressing mode.
+    const std::string &name1 = nameWithID(Opcodes[0]);
+    const std::string &name2 = nameWithID(Opcodes[1]);
+    if ((name1 == "VMOVDneon" && name2 == "VORRd") ||
+        (name1 == "VMOVQ" && name2 == "VORRq")) {
+      // Inserting the opening curly brace for this case block.
+      --Indentation; --Indentation;
+      o.indent(Indentation) << "{\n";
+      ++Indentation; ++Indentation;
+
+      o.indent(Indentation)
+        << "field_t N = fieldFromInstruction(insn, 7, 1), "
+        << "M = fieldFromInstruction(insn, 5, 1);\n";
+      o.indent(Indentation)
+        << "field_t Vn = fieldFromInstruction(insn, 16, 4), "
+        << "Vm = fieldFromInstruction(insn, 0, 4);\n";
+      o.indent(Indentation)
+        << "return (N == M && Vn == Vm) ? "
+        << Opcodes[0] << " /* " << name1 << " */ : "
+        << Opcodes[1] << " /* " << name2 << " */ ;\n";
+
+      // Inserting the closing curly brace for this case block.
+      --Indentation; --Indentation;
+      o.indent(Indentation) << "}\n";
+      ++Indentation; ++Indentation;
+
+      return true;
+    }
+    if (name1 == "LDR" && name2 == "LDRcp") {
+      o.indent(Indentation)
+        << "return " << Opcodes[0]
+        << "; // Returning LDR for {LDR, LDRcp}\n";
+      return true;
+    }
+    if (name1 == "tLDM" && name2 == "tLDM_UPD") {
+      // Inserting the opening curly brace for this case block.
+      --Indentation; --Indentation;
+      o.indent(Indentation) << "{\n";
+      ++Indentation; ++Indentation;
+      
+      o.indent(Indentation)
+        << "unsigned Rn = fieldFromInstruction(insn, 8, 3), "
+        << "list = fieldFromInstruction(insn, 0, 8);\n";
+      o.indent(Indentation)
+        << "return ((list >> Rn) & 1) == 0 ? "
+        << Opcodes[1] << " /* " << name2 << " */ : "
+        << Opcodes[0] << " /* " << name1 << " */ ;\n";
+
+      // Inserting the closing curly brace for this case block.
+      --Indentation; --Indentation;
+      o.indent(Indentation) << "}\n";
+      ++Indentation; ++Indentation;
+
+      return true;
+    }
+    if (sameStringExceptSuffix(name1, name2, "_UPD")) {
+      o.indent(Indentation)
+        << "return fieldFromInstruction(insn, 0, 4) == 15 ? " << Opcodes[0]
+        << " /* " << name1 << " */ : " << Opcodes[1] << "/* " << name2
+        << " */ ; // Advanced SIMD addressing mode\n";
+      return true;
+    }
+
+    // Otherwise, it does not belong to the known conflict sets.
+  }
+  // We don't know how to decode these instructions!  Dump the conflict set!
+  o.indent(Indentation) << "return 0;" << " // Conflict set: ";
+  for (int i = 0, N = Opcodes.size(); i < N; ++i) {
+    o << nameWithID(Opcodes[i]);
+    if (i < (N - 1))
+      o << ", ";
+    else
+      o << '\n';
+  }
+  return true;
+}
+
+
+////////////////////////////////////////////
+//                                        //
+//  ARMDEBackend                          //
+//  (Helper class for ARMDecoderEmitter)  //
+//                                        //
+////////////////////////////////////////////
+
+class ARMDecoderEmitter::ARMDEBackend {
+public:
+  ARMDEBackend(ARMDecoderEmitter &frontend) :
+    NumberedInstructions(),
+    Opcodes(),
+    Frontend(frontend),
+    Target(),
+    FC(NULL)
+  {
+    if (Target.getName() == "ARM")
+      TargetName = TARGET_ARM;
+    else {
+      errs() << "Target name " << Target.getName() << " not recognized\n";
+      assert(0 && "Unknown target");
+    }
+
+    // Populate the instructions for our TargetName.
+    populateInstructions();
+  }
+
+  ~ARMDEBackend() {
+    if (FC) {
+      delete FC;
+      FC = NULL;
+    }
+  }
+
+  void getInstructionsByEnumValue(std::vector<const CodeGenInstruction*>
+                                                &NumberedInstructions) {
+    // We must emit the PHI opcode first...
+    std::string Namespace = Target.getInstNamespace();
+    assert(!Namespace.empty() && "No instructions defined.");
+
+    NumberedInstructions = Target.getInstructionsByEnumValue();
+  }
+
+  bool populateInstruction(const CodeGenInstruction &CGI, TARGET_NAME_t TN);
+
+  void populateInstructions();
+
+  // Emits disassembler code for instruction decoding.  This delegates to the
+  // FilterChooser instance to do the heavy lifting.
+  void emit(raw_ostream &o);
+
+protected:
+  std::vector<const CodeGenInstruction*> NumberedInstructions;
+  std::vector<unsigned> Opcodes;
+  // Special case for the ARM chip, which supports ARM and Thumb ISAs.
+  // Opcodes2 will be populated with the Thumb opcodes.
+  std::vector<unsigned> Opcodes2;
+  ARMDecoderEmitter &Frontend;
+  CodeGenTarget Target;
+  FilterChooser *FC;
+
+  TARGET_NAME_t TargetName;
+};
+
+bool ARMDecoderEmitter::ARMDEBackend::populateInstruction(
+    const CodeGenInstruction &CGI, TARGET_NAME_t TN) {
+  const Record &Def = *CGI.TheDef;
+  const StringRef Name = Def.getName();
+  uint8_t Form = getByteField(Def, "Form");
+  BitsInit &Bits = getBitsField(Def, "Inst");
+
+  if (TN == TARGET_ARM) {
+    // FIXME: what about Int_MemBarrierV6 and Int_SyncBarrierV6?
+    if ((Name != "Int_MemBarrierV7" && Name != "Int_SyncBarrierV7") &&
+        Form == ARM_FORMAT_PSEUDO)
+      return false;
+    if (thumbInstruction(Form))
+      return false;
+    if (Name.find("CMPz") != std::string::npos /* ||
+        Name.find("CMNz") != std::string::npos */)
+      return false;
+
+    // Ignore pseudo instructions.
+    if (Name == "BXr9" || Name == "BMOVPCRX" || Name == "BMOVPCRXr9")
+      return false;
+
+    // VLDMQ/VSTMQ can be hanlded with the more generic VLDMD/VSTMD.
+    if (Name == "VLDMQ" || Name == "VLDMQ_UPD" ||
+        Name == "VSTMQ" || Name == "VSTMQ_UPD")
+      return false;
+
+    //
+    // The following special cases are for conflict resolutions.
+    //
+
+    // NEON NLdStFrm conflict resolutions:
+    //
+    // 1. Ignore suffix "odd" and "odd_UPD", prefer the "even" register-
+    //    numbered ones which have the same Asm format string.
+    // 2. Ignore VST2d64_UPD, which conflicts with VST1q64_UPD.
+    // 3. Ignore VLD2d64_UPD, which conflicts with VLD1q64_UPD.
+    // 4. Ignore VLD1q[_UPD], which conflicts with VLD1q64[_UPD].
+    // 5. Ignore VST1q[_UPD], which conflicts with VST1q64[_UPD].
+    if (Name.endswith("odd") || Name.endswith("odd_UPD") ||
+        Name == "VST2d64_UPD" || Name == "VLD2d64_UPD" ||
+        Name == "VLD1q" || Name == "VLD1q_UPD" ||
+        Name == "VST1q" || Name == "VST1q_UPD")
+      return false;
+
+    // RSCSri and RSCSrs set the 's' bit, but are not predicated.  We are
+    // better off using the generic RSCri and RSCrs instructions.
+    if (Name == "RSCSri" || Name == "RSCSrs") return false;
+
+    // MOVCCr, MOVCCs, MOVCCi, FCYPScc, FCYPDcc, FNEGScc, and FNEGDcc are used
+    // in the compiler to implement conditional moves.  We can ignore them in
+    // favor of their more generic versions of instructions.
+    // See also SDNode *ARMDAGToDAGISel::Select(SDValue Op).
+    if (Name == "MOVCCr" || Name == "MOVCCs" || Name == "MOVCCi" ||
+        Name == "FCPYScc" || Name == "FCPYDcc" ||
+        Name == "FNEGScc" || Name == "FNEGDcc")
+      return false;
+
+    // Ditto for VMOVDcc, VMOVScc, VNEGDcc, and VNEGScc.
+    if (Name == "VMOVDcc" || Name == "VMOVScc" || Name == "VNEGDcc" ||
+        Name == "VNEGScc")
+      return false;
+
+    // Ignore the *_sfp instructions when decoding.  They are used by the
+    // compiler to implement scalar floating point operations using vector
+    // operations in order to work around some performance issues.
+    if (Name.find("_sfp") != std::string::npos) return false;
+
+    // LDM_RET is a special case of LDM (Load Multiple) where the registers
+    // loaded include the PC, causing a branch to a loaded address.  Ignore
+    // the LDM_RET instruction when decoding.
+    if (Name == "LDM_RET") return false;
+
+    // Bcc is in a more generic form than B.  Ignore B when decoding.
+    if (Name == "B") return false;
+
+    // Ignore the non-Darwin BL instructions and the TPsoft (TLS) instruction.
+    if (Name == "BL" || Name == "BL_pred" || Name == "BLX" || Name == "BX" ||
+        Name == "TPsoft")
+      return false;
+
+    // Ignore VDUPf[d|q] instructions known to conflict with VDUP32[d-q] for
+    // decoding.  The instruction duplicates an element from an ARM core
+    // register into every element of the destination vector.  There is no
+    // distinction between data types.
+    if (Name == "VDUPfd" || Name == "VDUPfq") return false;
+
+    // A8-598: VEXT
+    // Vector Extract extracts elements from the bottom end of the second
+    // operand vector and the top end of the first, concatenates them and
+    // places the result in the destination vector.  The elements of the
+    // vectors are treated as being 8-bit bitfields.  There is no distinction
+    // between data types.  The size of the operation can be specified in
+    // assembler as vext.size.  If the value is 16, 32, or 64, the syntax is
+    // a pseudo-instruction for a VEXT instruction specifying the equivalent
+    // number of bytes.
+    //
+    // Variants VEXTd16, VEXTd32, VEXTd8, and VEXTdf are reduced to VEXTd8;
+    // variants VEXTq16, VEXTq32, VEXTq8, and VEXTqf are reduced to VEXTq8.
+    if (Name == "VEXTd16" || Name == "VEXTd32" || Name == "VEXTdf" ||
+        Name == "VEXTq16" || Name == "VEXTq32" || Name == "VEXTqf")
+      return false;
+
+    // Vector Reverse is similar to Vector Extract.  There is no distinction
+    // between data types, other than size.
+    //
+    // VREV64df is equivalent to VREV64d32.
+    // VREV64qf is equivalent to VREV64q32.
+    if (Name == "VREV64df" || Name == "VREV64qf") return false;
+
+    // VDUPLNfd is equivalent to VDUPLN32d; VDUPfdf is specialized VDUPLN32d.
+    // VDUPLNfq is equivalent to VDUPLN32q; VDUPfqf is specialized VDUPLN32q.
+    // VLD1df is equivalent to VLD1d32.
+    // VLD1qf is equivalent to VLD1q32.
+    // VLD2d64 is equivalent to VLD1q64.
+    // VST1df is equivalent to VST1d32.
+    // VST1qf is equivalent to VST1q32.
+    // VST2d64 is equivalent to VST1q64.
+    if (Name == "VDUPLNfd" || Name == "VDUPfdf" ||
+        Name == "VDUPLNfq" || Name == "VDUPfqf" ||
+        Name == "VLD1df" || Name == "VLD1qf" || Name == "VLD2d64" ||
+        Name == "VST1df" || Name == "VST1qf" || Name == "VST2d64")
+      return false;
+  } else if (TN == TARGET_THUMB) {
+    if (!thumbInstruction(Form))
+      return false;
+
+    // Ignore pseudo instructions.
+    if (Name == "tInt_eh_sjlj_setjmp" || Name == "t2Int_eh_sjlj_setjmp" ||
+        Name == "t2MOVi32imm" || Name == "tBX" || Name == "tBXr9")
+      return false;
+
+    // On Darwin R9 is call-clobbered.  Ignore the non-Darwin counterparts.
+    if (Name == "tBL" || Name == "tBLXi" || Name == "tBLXr")
+      return false;
+
+    // Ignore the TPsoft (TLS) instructions, which conflict with tBLr9.
+    if (Name == "tTPsoft" || Name == "t2TPsoft")
+      return false;
+
+    // Ignore tLEApcrel and tLEApcrelJT, prefer tADDrPCi.
+    if (Name == "tLEApcrel" || Name == "tLEApcrelJT")
+      return false;
+
+    // Ignore t2LEApcrel, prefer the generic t2ADD* for disassembly printing.
+    if (Name == "t2LEApcrel")
+      return false;
+
+    // Ignore tADDrSP, tADDspr, and tPICADD, prefer the generic tADDhirr.
+    // Ignore t2SUBrSPs, prefer the t2SUB[S]r[r|s].
+    // Ignore t2ADDrSPs, prefer the t2ADD[S]r[r|s].
+    if (Name == "tADDrSP" || Name == "tADDspr" || Name == "tPICADD" ||
+        Name == "t2SUBrSPs" || Name == "t2ADDrSPs")
+      return false;
+
+    // Ignore t2LDRDpci, prefer the generic t2LDRDi8, t2LDRD_PRE, t2LDRD_POST.
+    if (Name == "t2LDRDpci")
+      return false;
+
+    // Ignore t2TBB, t2TBH and prefer the generic t2TBBgen, t2TBHgen.
+    if (Name == "t2TBB" || Name == "t2TBH")
+      return false;
+
+    // Resolve conflicts:
+    //
+    //   tBfar conflicts with tBLr9
+    //   tCMNz conflicts with tCMN (with assembly format strings being equal)
+    //   tPOP_RET/t2LDM_RET conflict with tPOP/t2LDM (ditto)
+    //   tMOVCCi conflicts with tMOVi8
+    //   tMOVCCr conflicts with tMOVgpr2gpr
+    //   tBR_JTr conflicts with tBRIND
+    //   tSpill conflicts with tSTRspi
+    //   tLDRcp conflicts with tLDRspi
+    //   tRestore conflicts with tLDRspi
+    //   t2LEApcrelJT conflicts with t2LEApcrel
+    //   t2ADDrSPi/t2SUBrSPi have more generic couterparts
+    if (Name == "tBfar" ||
+        /* Name == "tCMNz" || */ Name == "tCMPzi8" || Name == "tCMPzr" ||
+        Name == "tCMPzhir" || /* Name == "t2CMNzrr" || Name == "t2CMNzrs" ||
+        Name == "t2CMNzri" || */ Name == "t2CMPzrr" || Name == "t2CMPzrs" ||
+        Name == "t2CMPzri" || Name == "tPOP_RET" || Name == "t2LDM_RET" ||
+        Name == "tMOVCCi" || Name == "tMOVCCr" || Name == "tBR_JTr" ||
+        Name == "tSpill" || Name == "tLDRcp" || Name == "tRestore" ||
+        Name == "t2LEApcrelJT" || Name == "t2ADDrSPi" || Name == "t2SUBrSPi")
+      return false;
+  }
+
+  // Dumps the instruction encoding format.
+  switch (TargetName) {
+  case TARGET_ARM:
+  case TARGET_THUMB:
+    DEBUG(errs() << Name << " " << stringForARMFormat((ARMFormat)Form));
+    break;
+  }
+
+  DEBUG({
+      errs() << " ";
+
+      // Dumps the instruction encoding bits.
+      dumpBits(errs(), Bits);
+
+      errs() << '\n';
+
+      // Dumps the list of operand info.
+      for (unsigned i = 0, e = CGI.OperandList.size(); i != e; ++i) {
+        CodeGenInstruction::OperandInfo Info = CGI.OperandList[i];
+        const std::string &OperandName = Info.Name;
+        const Record &OperandDef = *Info.Rec;
+
+        errs() << "\t" << OperandName << " (" << OperandDef.getName() << ")\n";
+      }
+    });
+
+  return true;
+}
+
+void ARMDecoderEmitter::ARMDEBackend::populateInstructions() {
+  getInstructionsByEnumValue(NumberedInstructions);
+
+  uint16_t numUIDs = NumberedInstructions.size();
+  uint16_t uid;
+
+  const char *instClass = NULL;
+
+  switch (TargetName) {
+  case TARGET_ARM:
+    instClass = "InstARM";
+    break;
+  default:
+    assert(0 && "Unreachable code!");
+  }
+
+  for (uid = 0; uid < numUIDs; uid++) {
+    // filter out intrinsics
+    if (!NumberedInstructions[uid]->TheDef->isSubClassOf(instClass))
+      continue;
+
+    if (populateInstruction(*NumberedInstructions[uid], TargetName))
+      Opcodes.push_back(uid);
+  }
+
+  // Special handling for the ARM chip, which supports two modes of execution.
+  // This branch handles the Thumb opcodes.
+  if (TargetName == TARGET_ARM) {
+    for (uid = 0; uid < numUIDs; uid++) {
+      // filter out intrinsics
+      if (!NumberedInstructions[uid]->TheDef->isSubClassOf("InstARM")
+          && !NumberedInstructions[uid]->TheDef->isSubClassOf("InstThumb"))
+        continue;
+
+      if (populateInstruction(*NumberedInstructions[uid], TARGET_THUMB))
+        Opcodes2.push_back(uid);
+    }
+  }
+}
+
+// Emits disassembler code for instruction decoding.  This delegates to the
+// FilterChooser instance to do the heavy lifting.
+void ARMDecoderEmitter::ARMDEBackend::emit(raw_ostream &o) {
+  switch (TargetName) {
+  case TARGET_ARM:
+    Frontend.EmitSourceFileHeader("ARM/Thumb Decoders", o);
+    break;
+  default:
+    assert(0 && "Unreachable code!");
+  }
+
+  o << "#include \"llvm/Support/DataTypes.h\"\n";
+  o << "#include <assert.h>\n";
+  o << '\n';
+  o << "namespace llvm {\n\n";
+
+  FilterChooser::setTargetName(TargetName);
+
+  switch (TargetName) {
+  case TARGET_ARM: {
+    // Emit common utility and ARM ISA decoder.
+    FC = new FilterChooser(NumberedInstructions, Opcodes);
+    // Reset indentation level.
+    unsigned Indentation = 0;
+    FC->emitTop(o, Indentation);
+    delete FC;
+
+    // Emit Thumb ISA decoder as well.
+    FilterChooser::setTargetName(TARGET_THUMB);
+    FC = new FilterChooser(NumberedInstructions, Opcodes2);
+    // Reset indentation level.
+    Indentation = 0;
+    FC->emitBot(o, Indentation);
+    break;
+  }
+  default:
+    assert(0 && "Unreachable code!");
+  }
+
+  o << "\n} // End llvm namespace \n";
+}
+
+/////////////////////////
+//  Backend interface  //
+/////////////////////////
+
+void ARMDecoderEmitter::initBackend()
+{
+    Backend = new ARMDEBackend(*this);
+}
+
+void ARMDecoderEmitter::run(raw_ostream &o)
+{
+  Backend->emit(o);
+}
+
+void ARMDecoderEmitter::shutdownBackend()
+{
+  delete Backend;
+  Backend = NULL;
+}

Added: llvm/trunk/utils/TableGen/ARMDecoderEmitter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/ARMDecoderEmitter.h?rev=100233&view=auto
==============================================================================
--- llvm/trunk/utils/TableGen/ARMDecoderEmitter.h (added)
+++ llvm/trunk/utils/TableGen/ARMDecoderEmitter.h Fri Apr  2 17:27:38 2010
@@ -0,0 +1,50 @@
+//===------------ ARMDecoderEmitter.h - Decoder Generator -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the ARM Disassembler.
+// It contains the tablegen backend declaration ARMDecoderEmitter.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ARMDECODEREMITTER_H
+#define ARMDECODEREMITTER_H
+
+#include "TableGenBackend.h"
+
+#include "llvm/Support/DataTypes.h"
+
+namespace llvm {
+
+class ARMDecoderEmitter : public TableGenBackend {
+  RecordKeeper &Records;
+public:
+  ARMDecoderEmitter(RecordKeeper &R) : Records(R) {
+    initBackend();
+  }
+    
+  ~ARMDecoderEmitter() {
+    shutdownBackend();
+  }
+	
+  // run - Output the code emitter
+  void run(raw_ostream &o);
+    
+private:
+  // Helper class for ARMDecoderEmitter.
+  class ARMDEBackend;
+
+  ARMDEBackend *Backend;
+    
+  void initBackend();
+  void shutdownBackend();
+};
+
+} // end llvm namespace
+
+#endif

Modified: llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp?rev=100233&r1=100232&r2=100233&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp (original)
+++ llvm/trunk/utils/TableGen/DisassemblerEmitter.cpp Fri Apr  2 17:27:38 2010
@@ -12,6 +12,8 @@
 #include "Record.h"
 #include "X86DisassemblerTables.h"
 #include "X86RecognizableInstr.h"
+#include "ARMDecoderEmitter.h"
+
 using namespace llvm;
 using namespace llvm::X86Disassembler;
 
@@ -124,6 +126,12 @@
     return;
   }
 
+  // Fixed-instruction-length targets use a common disassembler.
+  if (Target.getName() == "ARM") {
+    ARMDecoderEmitter(Records).run(OS);
+    return;
+  }  
+
   throw TGError(Target.getTargetRecord()->getLoc(),
                 "Unable to generate disassembler for this target");
 }

Modified: llvm/trunk/utils/TableGen/TableGen.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/utils/TableGen/TableGen.cpp?rev=100233&r1=100232&r2=100233&view=diff
==============================================================================
--- llvm/trunk/utils/TableGen/TableGen.cpp (original)
+++ llvm/trunk/utils/TableGen/TableGen.cpp Fri Apr  2 17:27:38 2010
@@ -31,6 +31,7 @@
 #include "OptParserEmitter.h"
 #include "Record.h"
 #include "RegisterInfoEmitter.h"
+#include "ARMDecoderEmitter.h"
 #include "SubtargetEmitter.h"
 #include "TGParser.h"
 #include "llvm/Support/CommandLine.h"
@@ -47,6 +48,7 @@
   GenEmitter,
   GenRegisterEnums, GenRegister, GenRegisterHeader,
   GenInstrEnums, GenInstrs, GenAsmWriter, GenAsmMatcher,
+  GenARMDecoder,
   GenDisassembler,
   GenCallingConv,
   GenClangDiagsDefs,
@@ -83,6 +85,8 @@
                                "Generate calling convention descriptions"),
                     clEnumValN(GenAsmWriter, "gen-asm-writer",
                                "Generate assembly writer"),
+                    clEnumValN(GenARMDecoder, "gen-arm-decoder",
+                               "Generate decoders for ARM/Thumb"),
                     clEnumValN(GenDisassembler, "gen-disassembler",
                                "Generate disassembler"),
                     clEnumValN(GenAsmMatcher, "gen-asm-matcher",
@@ -228,6 +232,9 @@
     case GenAsmWriter:
       AsmWriterEmitter(Records).run(*Out);
       break;
+    case GenARMDecoder:
+      ARMDecoderEmitter(Records).run(*Out);
+      break;
     case GenAsmMatcher:
       AsmMatcherEmitter(Records).run(*Out);
       break;





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